How to cultivate ginkgo? Master water and fertilizer management and pest and disease control techniques
Ginkgo is a major tree species for landscaping and afforestation. Its leaves resemble fans, are unique and beautiful, and have excellent ornamental value. Its cultivation has high medicinal value. Its wood is a raw material for making musical instruments and has high economic value. So how is ginkgo cultivated? Below, the editor will analyze it in detail for everyone.
I. Selection and planting of seedlings
Ginkgo seedlings with a trunk diameter under 5 cm can be planted bare-rooted, while those with a trunk diameter over 6 cm need to be cultivated with a soil ball. Bare-rooted seedlings have a recovery period in the first year, while seedlings planted with a soil ball can grow in the same year. After small seedlings are planted, they can simply be flood-irrigated. After planting, attention should be paid to the phenomenon of "false survival." When determining whether ginkgo has "false survival," do not only look at the ginkgo leaves; what matters is looking at the ginkgo roots.
II. Growth and management
1. Soil plowing. Ginkgo can grow normally in sandy soil, loam, clay, and gravelly soil. Good soil can meet ginkgo's needs for nutrients, water, and so on, so the soil should be plowed and improved in a timely manner. Soil plowing and improvement should be adapted to local conditions. Generally, deep plowing is 60-80 cm to improve the soil and prevent soil compaction. For young trees, open a ring-shaped trench 0.5 m outside the trunk, with a trench depth of 0.3 m and width of 0.4 m, and then expand it year by year until it grows into a mature large tree. In spring and summer, during the rapid growth period of new shoots and roots, shallow plowing should be carried out appropriately.
2. Fertilization. Organic fertilizer is mainly applied as base fertilizer. Base fertilizer is best applied in autumn, that is, in September-October combined with deep plowing, or from late October to mid-November, and sometimes it can also be applied before spring sprouting. Broadcast application is relatively beneficial for absorption by ginkgo roots in all directions, but it requires a larger amount of fertilizer and is not economical. Young trees commonly use ring-shaped trench application. Chemical fertilizer is mainly used for topdressing, preferably 3 times a year, and foliar spraying can also be carried out in combination with pest and disease control. The amount of fertilization is generally determined according to tree vigor, tree age, variety, soil, climate, and management level.
III. Drainage and irrigation
1. Irrigation. Ginkgo has relatively strong drought resistance. In areas with annual precipitation of about 1000 mm, mature trees and ancient ginkgo trees generally do not need irrigation. Ginkgo requires sufficient water at all stages of growth and development, so in arid areas, in dry seasons, and in sandy land with insufficient fertility and poor soil, timely irrigation should be carried out.
2. Drainage. Ginkgo is afraid of waterlogging. If water accumulates for 10 consecutive days to a depth exceeding 15 cm, it will cause ginkgo leaf drop and root rot, and in severe cases can cause ginkgo death. In the rainy season, special attention should be paid to drainage and waterlogging prevention to ensure that accumulated water can be discharged in time.
IV. Seedling transplantation
Transplantation should be chosen in spring as much as possible. When lifting ginkgo saplings, it is best to lift a soil ball 6 times the ground diameter of the sapling. The soil ball is generally dug into an apple shape, larger at the top and smaller at the bottom, and it is better if the lower part is slightly flat. The soil ball should be tied firmly with straw rope to protect it and prevent it from loosening. Generally, large trees need to be lifted with a crane. Transport vehicles should not load too many large seedlings; it is advisable to load 1 row of large seedlings per vehicle, and try not to stack large seedlings in layers to avoid squeezing each other.
Before planting, first check whether the depth of the tree hole and the height and width of the ginkgo soil ball are suitable. Note that the tree hole should not be dug too deep, as too much depth will cause poor plant growth. After the sapling is placed, before backfilling soil in the hole, first remove the straw rope from the soil ball, then fill half the soil and firm it, then fill in the other half of the soil and firm it again, build a tree basin around it and water it, and the water should soak through.
After ginkgo planting, supports should be set up in a timely manner, generally using three-stake supports. Wait 3-5 days after planting and water a second thorough watering, then water thoroughly once every 7-8 days. After 40 days, watering can be done reasonably according to soil moisture conditions.
V. Pest and disease control
1. Root rot. Root rot generally occurs in June. Control methods: ① Remove diseased plants in time and burn them in a centralized manner; ② Spray with 70% thiophanate-methyl 1000-fold solution for control.
2. Stem rot and leaf blight. Control method: Continuously spray carbendazim 800-fold solution for control.
3. Ginkgo tussock moth. Control methods: ① Biological control. During the female moth's egg-laying period, release natural enemies such as Trichogramma. ② Light trapping. Use the phototaxis of adult ginkgo tussock moths and use black light lamps to trap and kill them. ③ Manual capture. Collect egg masses and cocoons and kill them; capture and kill mature larvae. ④ Chemical control. Spray 90% trichlorfon 1500-2000-fold solution, or 50% dichlorvos emulsifiable concentrate, malathion emulsifiable concentrate 1000-fold solution, or 2.5% deltamethrin 3000-5000-fold solution.
4. White grubs. Control methods: ① Manual capture: Dig deeply under newly damaged plants, find the larvae, and handle them in a centralized manner. ② Chemical control: Chemicals can be used to drench the roots. Root drenching should be done in the early morning or evening. Use a fork to make small holes 10 cm deep and 2 cm apart, and pour 25% phoxim emulsifiable concentrate 300-fold solution into the small holes. Or use 40% isofenphos-methyl 1500-2000-fold solution to irrigate the nursery land once every 7-10 days, for 2-3 consecutive times. ③ Toxic soil control: For each mu of nursery land, use 1.5-2.5 kg of 3% trichlorfon powder or 2.5 kg of 3% carbofuran granules, add 25-50 kg of fine soil, mix evenly, and spread evenly on the soil surface.
Ginkgo combines ornamental value, edible value, medicinal value, and economic value in one. It is an excellent landscaping seedling and is currently the preferred tree species for urban landscaping. The above are detailed techniques for ginkgo cultivation, water and fertilizer management, and pest and disease control, and we hope they are helpful to growers.
Catalpa cultivation and pest and disease control techniques
Catalpa, also known as golden-thread catalpa, is a deciduous tree in the genus Catalpa of the Bignoniaceae family. It is mainly produced in China's Yellow River basin and Yangtze River basin, and is also distributed in North China and the Zhejiang-Anhui area. The catalpa trunk is tall and straight and grows rapidly. It is suitable as a shade tree and street tree, and can also be used to accent lawns and rockeries. It is a good material for landscape greening. Its cultivation and management techniques are introduced below for reference only.
Morphological characteristics and ecological habits
Catalpa can reach a height of 35 m. The trunk is tall and straight, and the crown is obovate. The bark is gray or dark brown with shallow longitudinal fissures. Old trees have tumor-like protrusions on the trunk, and young branches are grayish green and hairless. Leaves are opposite or in whorls of three, triangular-ovate or long-ovate-elliptic, with a gradually pointed apex, and a truncate to broadly cuneate or cordate base, 5 cm to 17 cm long, entire, with purple glandular spots on the back. Racemes are terminal, with 3 to 12 flowers, and the corolla is light pink with purple spots inside. Capsules are 25 cm to 45 cm long and about 5 mm in diameter, and seeds are flat with white long hairs at both ends. The flowering period is April to May, and the fruiting period is September to October.
Catalpa likes light, and seedlings are slightly shade-tolerant. It likes a warm and humid climate, but is not resistant to severe cold. Catalpa is neither drought-tolerant nor waterlogging-tolerant, and is not tolerant of barrenness. It likes moist, fertile, well-aerated sandy loam, and can tolerate mildly saline-alkaline soil. It can grow normally in mildly saline-alkaline soil with pH 8.8 and a salt content of 0.15%. It has strong resistance to sulfur dioxide and chlorine gas, and has a strong dust-retention capacity.
Planting methods
In landscaping, catalpa can be planted in both spring and autumn. The spring planting time is from late March to mid-April, and autumn planting should be carried out from mid-November to early December. Before planting, dig the planting holes as required. The size of the planting hole should be no less than 1.2 m × 1.2 m, with a depth of no less than 80 cm. Topsoil and subsoil should be piled separately. If the soil quality does not meet the requirements, soil replacement should also be carried out. Catalpa with a DBH of less than 10 cm can be planted bare-rooted, while seedlings larger than 10 cm are best planted with a soil ball, which can maintain a relatively high survival rate. When planting catalpa, be sure not to plant too deep, as planting too deep can easily cause the plant to suffer from suppressed buds. Even for seedlings planted in autumn, the soil mound should be opened when watering in early spring of the following year, which is beneficial for the plant to sprout. Generally speaking, when planting bare-rooted seedlings, the soil can be filled 2 cm to 3 cm above the original soil mark, while seedlings with soil balls should be level with the original soil ball. Catalpa likes fertilizer, so some decomposed and fermented barnyard manure should be applied as base fertilizer during planting. The base fertilizer should be mixed evenly with the planting soil; if not mixed evenly, it is easy to burn the roots.
When planting in spring, water the first watering immediately, water the second after three days, and water the third after another five days. For autumn planting, the number of waterings should be determined according to the planting time. If planted in mid-November, two thorough waterings can be given, that is, water the first immediately after planting and water the second after seven days; if planted in early December, one thorough watering is enough. After planting, supports should be set up in time for larger seedlings to prevent wind blowing or artificial shaking.
Water and fertilizer management
Catalpa has relatively strict requirements for water, which should be emphasized in daily maintenance. Taking seedlings planted in spring as an example, in addition to watering the first three waterings well, one to two thorough waterings should also be given in May, June, September, and October. July and August are periods of abundant precipitation, so if it is not excessively dry, watering can be omitted. In early December, enough anti-freezing water should be given thoroughly. In early March of the following year, green-returning water should be given in time. In April, May, June, September, and October, one to two thorough waterings should be given each month, and anti-freezing water should be given in early December. In the third year, watering can follow the method for the second year. After the fourth year, in addition to watering green-returning water and anti-freezing water well, the plant can rely on natural precipitation for growth, but when the weather is too dry and precipitation is low, it should still be watered. For some street trees that have grown for many years, watering should also be done during drought, which is beneficial to plant growth and prolonging life.
Catalpa likes fertilizer. In addition to applying sufficient base fertilizer at planting, some decomposed and fermented sesame paste residue or cow and horse manure should also be applied at the end of autumn each year combined with watering anti-freezing water. In early May, some urea can be applied to the plant, which can make the branches and leaves luxuriant and accelerate growth. In late July, applying some phosphorus and potassium fertilizer can effectively improve the lignification degree of the plant's branches and help the plant overwinter safely.
Pruning and shaping
Catalpa is tolerant of pruning and has relatively strong sprouting ability. Before planting, catalpa is generally subjected to trunk truncation, and the trunk height can be determined according to use requirements or design requirements. In spring, when new shoots have grown to about 30 cm, among the branches closer to the top, select three or four branches with strong growth, even distribution, and not on the same trajectory as main branches, and prune all other new shoots. During the growth period, the trunk will also sprout some buds, which should be removed in time to prevent excessive nutrient consumption. New branches of catalpa grow relatively quickly and can reach 80 cm to 120 cm in the same year. After leaf fall in late autumn, perform medium-short cutting on the selected main branches, retaining 40 cm to 60 cm, and be sure to retain outward-facing buds.
During cultivation and management, some people often do not perform short cutting on the main branches and let them grow freely. The result of doing so is that the catalpa crown becomes narrow and not spreading, which is neither beautiful nor provides a small shading area. Therefore, performing medium-short cutting on the main branches and selecting and retaining outward-facing buds is a favorable measure for expanding the catalpa crown. In late spring of the second year, screen the new small branches on the main branches, retaining one or two new branches on each main branch as side branches. The selected branches should be robust in growth and must not cross each other, and all other branches should be removed. After leaf fall in late autumn, perform medium-short cutting on these branches again, likewise retaining outward-facing buds. After the above pruning, the basic tree shape of catalpa is formed. In subsequent maintenance, it is only necessary to remove drooping branches, crossing branches, excessively dense branches, diseased and pest-infested branches, and dead and dry branches.
Pest and disease control
1. Common pests Pyrrhocoris similis, Paulownia tortoise beetle, Lymantria monacha, white kidney noctuid, Psilogramma menephron, ginkgo tussock moth, catalpa pyralid, green leafhopper, etc.
If Pyrrhocoris similis occurs, spray 20% Confidor soluble concentrate 3000-fold solution during the adult and nymph stages to kill it; if Paulownia tortoise beetle occurs, spray 3% high-permeability fenoxycarb emulsifiable concentrate 3000-fold solution during the young larval stage to kill it; if Lymantria monacha occurs, spray 20% Confidor soluble concentrate 3000-fold solution during the larval stage to kill it; if white kidney noctuid occurs, spray 48% Bacillus thuringiensis during the larval stage to kill it, and use 20% diflubenzuron suspension concentrate 7000-fold solution to kill larvae before the 3rd instar; when Psilogramma menephron occurs severely, spray Bt emulsion 500-fold solution to kill it; when catalpa pyralid occurs, spray 10% imidacloprid wettable powder 1000-fold solution for control; when green leafhopper causes damage, spray 25% buprofezin wettable granules 1000-fold solution or 48% chlorpyrifos emulsifiable concentrate 3500-fold solution during the nymph stage.
2. Common diseases These include catalpa anthracnose and catalpa root-knot nematode disease.
Catalpa anthracnose mainly damages catalpa leaves and tender shoots, and is prone to occur during periods of high temperature and high humidity and in environments with poor ventilation. After onset, leaves wilt and fall off. During maintenance, attention should be paid to ventilation and light transmission, and water and fertilizer management should be strengthened to improve the plant's disease resistance. If it occurs, spray 80% carbendazim wettable granules 500-fold solution for control, once every seven days, for three to four consecutive sprays to effectively control the disease.
Catalpa root-knot nematode disease mainly damages the root system of catalpa. The main root, lateral roots, and small roots can all be infected. After onset, some tumor-like structures grow on the root system, and then the root system rots, causing the plant to gradually wither and die. This disease is relatively stubborn. Before planting, quarantine should be strengthened to prevent the introduction of diseased seedlings. If it occurs, 10% fosthiazate powder (3 kg to 4 kg per mu) or 98% dazomet micro-powder (5 kg to 6 kg per mu) can be applied to the roots for control.
Propagation methods
Catalpa propagation can use sowing, root burial, cutting, and grafting methods. The commonly used methods are root burial and grafting.
1. Root burial method In late March, select root segments 1 cm to 2 cm thick and 12 cm to 20 cm long from robust catalpa trees with a DBH of more than 15 cm, and the cut should be smooth. Bury them diagonally into the soil, with a plant-row spacing of 20 cm × 20 cm, with the thick end facing up and the thin end facing down. When burying roots, be careful to press the soil firmly so that the roots and soil are closely combined. The upper end of the root should be slightly 2 cm below the ground. After burying, tread lightly, and then water thoroughly.
The flat burial method is to place the root segments flat in the trench and fill and firm the soil. The plant-row spacing is 30 cm × 30 cm. About 20 days after root burial, they can sprout. When the seedlings are about 15 cm tall, remove tillers in time, retaining only one robust branch per root segment. In early May, apply urea once at 50 kg/mu, which can accelerate seedling growth. In mid-June, apply a phosphorus-potassium compound fertilizer again to improve the lignification degree of the seedlings. In the second year, transplant the seedlings with a plant-row spacing of 60 cm × 60 cm.
2. Grafting method For grafting catalpa, use Catalpa ovata seedlings as rootstock. In late March, sow Catalpa ovata seeds by drilling. One month after the seedlings emerge completely, apply urea once at 50 kg per mu to accelerate seedling growth. In mid-April of the second year, use the bud grafting method for grafting. After grafting, cover the grafted bud with a plastic bag to retain moisture. After the bud survives, remove the plastic bag.
Year-round pest and disease control for garden trees
January1. January climate characteristics: dry and cold weather, little or no rain, and frequent fog. A warm winter is beneficial for pests and diseases to overwinter and breed.
2. Pest and disease occurrence this month: The main affected varieties this month are Ficus microcarpa thrips, Ficus altissima looper, scale insects, Hibiscus rosa-sinensis, Michelia alba aphids, and scale insects. Lagerstroemia speciosa borers. Willow canker.
3. Main pests and diseases in January and control methods: Mainly aphids, thrips, scale insects, borers, powdery mildew, brown spot, etc. For control, spray omethoate plus dichlorvos plus thiophanate 800-fold solution. For borers, inject omethoate diluted 5 to 10 times with water for poisoning, and cut off affected branches and burn them in a safe place.
4. Key points of cultivation management: Winter pruning: comprehensively carry out shaping and pruning of deciduous trees; prune dead branches, damaged branches, and diseased and pest-infested branches on large and small trees. This month, focus on watering to retain moisture and loosening soil to clean the garden. Cut off diseased, dead, and dry branches and dead trees in time.
5. Do a good job in sanitation and cleaning, and remove garbage in time.
6. For scale insects that are difficult to control, use the high-efficiency scale-killing agent Kuangshajie 1000-fold solution for control, and it can also control multiple pests at the same time.
February
February: The temperature has risen somewhat compared with last month, and trees are still in a dormant state.
1. Maintenance is basically the same as in January.
2. Pruning: Continue pruning dead branches and diseased branches of plane trees and large and small trees. Complete pruning of all kinds of trees before the end of the month.
3. Pest control: Continue to focus on controlling stinging moths and scale insects.
March
In March, control should mainly target the overwintering generation of pests and diseases.
I. A warm winter will cause the overwintering generation larvae of pests to become more active. The control of the overwintering generation of pests should be one of the key points of pest control in March. Among pests that overwinter as mature larvae, the following two should be noted:
1. Large bagworm, which overwinters as mature larvae in bags, mainly found in greater numbers on trees such as camphor, cherry blossom, cypress species, and osmanthus. In March, overwintering ends and they begin to damage tree leaves, and pupate at the end of March. Therefore, remove the insect bags in early March.
2. Scarab beetles, which overwinter as larvae (white grubs) in the soil, mainly distributed in the root-zone soil of ground cover plants such as dwarf lilyturf and rain lily and lawns. They will begin to cause damage in March, and pupate in April-May. Therefore, combine intertillage and soil turning to kill them, reduce the base population, which is extremely beneficial for subsequent control. Dihaiping can be used for control.
II. Another key point of control in March should be aphid control. The rise in temperature in March will lead to large-scale breeding of aphids. Aphids have now been found causing damage on many plants, such as coral, Euonymus japonicus, firethorn, Pittosporum tobira, red-leaf plum, peach trees, etc. Maintenance units should promptly carry out control to avoid unnecessary losses. For control, spray pesticides such as imidacloprid agents (Yibianjing) or fenpropathrin (do not use too frequently, as resistance is easily developed).
III. Boxwood leafroller, due to temperature reasons, few overwintering larvae begin feeding, but there are sporadic occurrences, and instars vary. Activity increases in early March, so control should be carried out early to prevent an outbreak of the next generation. Its first generation is expected to occur at the end of March, so observation should be strengthened and timely control carried out. For control, spray pyrethroid and BT insecticides.
IV. Powdery mildew, which can infect seedlings of woody flowers such as Chinese rose and rose. The disease mainly occurs on leaves, and also damages tender stems, flowers, and fruits. It also appears sporadically on Mahonia fortunei and Euonymus japonicus. With rising temperatures, there may be a major outbreak. For control, spray Penkejun 1000-1500-fold solution or 50% Tianwei No. 3 1500-2000-fold solution once every 10-15 days, for 2-3 consecutive times, and combine with pruning to cut off diseased and pest-infested branches and leaves.
April
April is a key month for pest and disease control in garden plants. Close observation should be maintained, and the appropriate period should be seized for careful control.
I. Leaf-eating pests in April:
(1) Boxwood leafroller: In late April it enters the peak damage period. In severe cases, the leaves are eaten completely and the whole plant turns yellow and withers. In the early stage, 2500-fold diflubenzuron can be used, and for older larvae, 1000-fold 40% omethoate emulsifiable concentrate can be used for control.
(2) Scarab beetles: Use the adults' death-feigning behavior to shake them from the trees and kill them in a centralized manner, or use black light traps.
(3) American white moth: In mid-April, overwintering-generation adults of the American white moth emerge, and manual capture can be used for control.
(4) Sophora japonica looper: In late April, the first-generation larvae of the Sophora japonica looper begin to cause damage. The best period should be seized to spray diflubenzuron and the like.
II. Trunk-boring pests in April
In April, trunk-boring pests begin damaging and become active, mainly including rusty longhorn beetle, Asian longhorned beetle, and ailanthus snout weevil, etc. In addition to manual injection of chemicals, control should be carried out according to the habits of different pests. Zhuchong Yichaling can be used in advance, which can basically prevent tree pests for half a year.
III. Piercing-sucking pests in April
1. Aphids. The aphids that should be focused on controlling include: green peach aphid, rose long-tube aphid, willow black hairy aphid, Koelreuteria polymorphic aphid, cotton aphid, etc. The preferred pesticide for aphid control is the biological insecticide 1.2% nicotine anabasine emulsion 800-1000-fold. Other options include 40% omethoate emulsifiable concentrate 1000-fold, imidacloprid 2000-fold, etc. Note that organophosphorus insecticides should be used with caution on Rosaceae plants such as peach trees to prevent phytotoxicity.
2. Mealybugs such as Drosicha corpulenta and peach scale begin to become active and cause damage. Control methods mainly include applying toxic rings, and special scale-killing pesticides such as Kuangshajie can also be selected for control.
3. Spotted lanternfly begins hatching in late April. Groups of small nymphs concentrate on tender branches to cause damage. The favorable opportunity should be seized for control, and 1000-fold pyrethroid pesticides can be used.
In addition, in mid-April, work should be done well to bury and apply granules to control piercing-sucking pests such as spider mites.
IV. Underground pests in April
Attention should be paid to controlling white grubs. 1000-fold 50% phoxim emulsifiable concentrate can be used for spraying and irrigation, or Dihaiping can be broadcast.
V. Diseases in April
This month, some diseases are in the initial infection stage, such as Euonymus japonicus powdery mildew and Chinese rose black spot. This month should mainly focus on prevention. The key control target in this period is canker disease of various tree species. The main control methods are strengthening water and fertilizer management and applying chemical treatments.
May
Entering May, the climate gradually warms further, and the occurrence of some flower pests and diseases also increases accordingly. The occurrence and control methods of several more serious pests and diseases are introduced below:
I. Aphids. Also called greasy insects. Hibiscus syriacus, ornamental peach, Chinese hibiscus, Chinese rose, honeysuckle, oleander, chrysanthemum, etc. are all easily damaged by aphids. This insect has multiple generations a year, overwinters as eggs on plant branches, and in April-May of the following year produces winged aphids that fly to hosts such as chrysanthemum and Chinese hibiscus to suck sap and cause damage. In late autumn in October, winged migrating aphids are produced, migrating from summer hosts to winter hosts, producing sexual wingless female aphids and male aphids flying from elsewhere. After mating, they lay eggs and overwinter as eggs. Control methods: ① Protect and utilize natural enemies. In addition to protecting natural enemies that exist in nature, some ladybugs and lacewings can already be artificially reared and released in time. ② Chemical control. Use broad-spectrum insecticides as little as possible, and choose systemic insecticides with less lethality to natural enemies. For garden plants, low-toxicity insecticides such as imidacloprid and acetamiprid can be sprayed for control.
II. Scale insects. Also called flower lice. They cause relatively serious damage on plants such as Rohdea japonica, palm, Podocarpus macrophyllus, Magnolia denudata, Chinese rose, boxwood, and Pittosporum tobira.
III. Damping-off. This disease mainly damages plants such as pine, fir, crabapple, ginkgo, poplar, and poinsettia, with a very wide range of damage. Usually, seed buds rot before emerging, appearing as missing seedlings on the ground; before seedlings lignify, water-soaked brown spots appear at the base of the root stem; under humid conditions, the diseased part has brown mycelium and small soil-granule-like sclerotia. When the temperature is in the low 20s Celsius, newly sown flowers and tree seedlings or those sown at the beginning of autumn, as well as some flowers prone to root rot, are extremely likely to develop damping-off if soil moisture is high. Control methods: ① Before sowing, disinfect the soil with dexon or quintozene, which has outstanding control effects; ② Control watering during the tender seedling stage and do not make the soil too wet; ③ When diseased seedlings are first found, irrigate with amobam solution or use hymexazol or Miaojunling for spray treatment 1-2 times.
IV. Powdery mildew. This disease can damage many plants and flowers such as lawn grass, Chinese rose, Magnolia liliiflora, Euonymus japonicus, Impatiens balsamina, and smoke tree. It mainly occurs on leaves. Both sides of the leaves are covered with white powder, causing the leaves to shrink. The diseased spots are pale yellow and irregular. Later, many small black dots appear on the leaf surface, namely the cleistothecia of the pathogen. Control methods: ① Cultivation and maintenance prevention, pay attention to ventilation and light transmission for flowers, carry out moderate pruning to reduce the ladder of infection; avoid stuffy and humid environments and reduce leaf surface watering. ② Eliminate the pathogen. Powdery mildew mostly falls to the ground or into the surface soil with diseased leaves as cleistothecia. Remove diseased fallen leaves in time, turn the soil, and cover the soil under the plants with sterile soil to reduce the source of initial infection. ③ Apply less nitrogen fertilizer and more phosphorus and potassium fertilizer; ④ During the initial infection period, spray fungicides such as triadimefon (Fenxiuning) and diniconazole. At present, the special-effect agents are kresoxim-methyl (also known as Cuibei) and Penkejun.
June
The high-temperature and high-humidity weather in June is very suitable for the occurrence of pests and diseases. Some piercing-sucking garden pests will continue to cause damage, and the first generation of other pests has already occurred. We should seize the opportunity and focus on control.
1. American white moth: In recent years, the American white moth has caused severe damage to forest trees in northern regions, and many areas began deploying prevention and control work for the white moth in April. From late May to early June, adult American white moths can still be seen emerging, mating, and laying eggs. At present, a large number of larvae have hatched, forming initial webs, and the larval instars are mostly 1st-2nd instar. During this period, spray diflubenzuron 6000-fold solution to control larvae, and combine with manual cutting and removal of webs to kill larvae.
2. Sophora japonica looper: In early June, the first-generation Sophora japonica looper larvae have reached the 3rd instar and are about to enter the binge-feeding period. During this period, diflubenzuron 3000-fold solution can still be sprayed, and 1.2% bitter nicotine emulsion (nicotine anabasine) 1000-1500-fold solution can also be sprayed for control.
3. Other leaf-eating pests: Leaf-eating pests currently causing damage in northern regions include: Clostera anachoreta, Leucoma salicis, bagworms, gypsy moth, Mythimna turca, boxwood leafroller, etc. Inspection and control should be strengthened. During this period, contact poisons and fumigants should be used for controlling leaf-eating pests.
4. Drosicha corpulenta: In recent years, more and more areas in northern regions have experienced Drosicha corpulenta, and the situation is severe. This insect can be spread artificially through seedling transport (especially with soil balls), and can also spread with wind. Not killing the removed insect bodies and dumping them at will is also one of the transmission routes.
According to investigations, in early June, female adult Drosicha corpulenta have successively begun descending from trees to look for summering and overwintering sites to lay eggs. However, some insect bodies still continue to cause damage on branches. During this period, in addition to spraying contact poisons to control female adults, manpower should be organized to remove female adults descending from trees and entering walls and soil to lay eggs, reducing the overwintering base. During this period, grass binding can also be used for trapping and killing. After they have all descended from the trees, remove the grass and burn it.
5. Lagerstroemia scale: The Lagerstroemia scale occurring on pomegranate and crape myrtle is at the egg stage, with large numbers of eggs in egg sacs. In early June, the eggs can hatch. Manual scraping of egg sacs can be used for control.
6. Scale insects such as Parthenolecanium corni, Eulecanium gigantea, Unaspis euonymi, Eulecanium kuwanai, and Eulecanium sophoricola: In early June, all of the above scale insects are in the initial hatching stage of nymphs. Inspection should be carried out promptly. Once crawling newly hatched nymphs are seen on branches and leaves, pesticide spraying can begin. For pesticides, spray Kuangshajie 1000-fold solution or 1.2% bitter nicotine emulsion (nicotine anabasine) 1000-fold solution; after newly hatched nymphs begin to secrete wax, spray Mieshaxing 1000-1500-fold solution or 10% imidacloprid wettable powder 2000-fold solution for control. Special-effect agents for scale insects such as Kuangshajie 800-1000-fold solution or Supusha 800-1000-fold solution can be used.
7. Psyllids: The three psyllids commonly occurring in northern regions, namely Albizia psyllid, Gleditsia psyllid, and Firmiana psyllid, all occur in early June. Spray 1.2% bitter nicotine emulsion (nicotine anabasine) 1000-fold solution or 10% imidacloprid 2000-fold solution for control in time. Control of this insect should follow the principle of early control and small control, otherwise later it will cause leaf drop and sooty mold, affecting the landscape and polluting the environment.
8. Aphids: Among aphids occurring on flowering shrubs in June, the more serious ones are peach powdery aphid, Spiraea aphid, and cotton aphid, and individual occurrences include peach tuber aphid. Among aphids occurring on trees, the more serious ones are Koelreuteria polymorphic hairy aphid, willow black hairy aphid, poplar hairy aphid, and sophora aphid, and individual occurrences of maple polymorphic hairy aphid are also very serious. During this period, chemical control should be carried out well. For pesticides, 1.2% bitter nicotine emulsion (nicotine anabasine) 1000-fold solution, 10% imidacloprid 2000-fold solution, or Mieshaxing 1000-1500-fold solution can be selected.
9. Red spider mites: Hawthorn spider mite, this mite causes serious damage on flowering shrubs such as Malus spectabilis, ornamental peach, and purple-leaf plum. The opportunity should be seized to kill it in early June, otherwise it will cause leaf scorching and leaf drop. In recent years, red spider mites have occurred seriously on trees. Trees with red spider mite occurrence include: Toona sinensis, Sophora japonica, black locust, ash, Euonymus bungeanus, Chinaberry, mulberry, elm, willow, and poplar. This year, emphasis should be placed on controlling red spider mites on plane trees. For control, 1.8% abamectin 6000-fold solution can be selected.
10. Asian longhorned beetle: In late May, the Asian longhorned beetle will begin emerging. Once new emergence holes are found, chemical control of adults can begin. Spray Green Weilei 200-300-fold solution, mainly spraying branches and trunks. When adult emergence is large and they feed heavily, damaging new branches, spray 1000-fold 1.2% bitter nicotine emulsion (nicotine anabasine) on the crown and new branches for control. At present, for larvae that continue to cause damage, injection chemicals should be used for control.
11. Small carpenter moth: In early June, adults will emerge. At present, some larvae are still causing damage in the xylem, and injection chemicals should be used for control.
12. Ailanthus snout weevil: For damage by Ailanthus snout weevil larvae, injection control can be used. For adults, spraying Green Weilei 200-300-fold solution can be used for control.
July
July: The temperature is the highest, and after mid-month there will be strong winds and heavy rain.
1. Transplant evergreens: During the rainy season, with sufficient water, conifers and bamboos can be transplanted, but pay attention to weather changes and water in time when high temperatures occur.
2. Drainage: After heavy rain, drain water in time.
3. Topdressing: Before rain, dry-apply quick-acting fertilizers such as nitrogen fertilizer.
4. Street trees: Carry out typhoon-prevention bud-stripping pruning. Prune all branches that conflict with power lines, and check tree stakes one by one. If looseness or instability is found, immediately straighten and tie them firmly. Prepare in advance in terms of labor organization, materials, tools, and equipment, and send personnel to inspect at any time, handling dangerous situations promptly.
5. Pest and disease control: Continue to control longhorned beetles and stinging moths. For longhorned beetle control, inject 50% fenitrothion 1:50-fold solution (or Guoshu Bao, or Yuanke No. 3) and then seal the hole, which can also achieve very good results. Camphor tree bagworm nests should be cut off in time and the insect nests destroyed to prevent repeated damage.
August
1. Weeds in various green spaces are still growing severely, slowing somewhat in late August, but the proportion of seed-setting weeds increases, so weed control cannot be relaxed.
2. Some flowering shrubs should be properly pruned of leggy branches to ensure luxuriant autumn shoots.
3. For the following 10 plants in various green spaces, especially newly built green spaces (ginkgo, persimmon, cherry blossom, lilac, ornamental peach, Albizia julibrissin, Prunus triloba, Acer mono, black locust, and cedar), close attention should still be paid to drainage, silt removal, and enhanced water permeability and aeration.
4. For newly built green spaces (roads), do not rush to remove shade nets for evergreens and large-specification trees. August's "three strong" climate (strong radiation, strong light, strong transpiration) is still relatively obvious.
[Main diseases]
1. Powdery mildew
Pest targets: Euonymus fortunei, Euonymus japonicus, and roses.
Control: 20% triadimefon at 1000-1500 times dilution.
2. Leaf blight
Pest targets: various flowering shrubs and cool-season turfgrass.
Control: 70% thiophanate-methyl at 1200 times dilution + 50% chlorothalonil at 600 times dilution.
3. Pythium blight
Pest targets: turfgrass and groundcover bedding flowers (petunias, etc.).
Control: spray 40% metalaxyl at 800-**** times dilution or 50% ridomil MZ at 500-600 times dilution.
[Main insect pests]
1. Box tree pyralid (Diaphania perspectalis)
Hosts: small-leaved box (Buxus sinica var. parvifolia), box-leaf euonymus, and Chinese boxwood.
Occurrence pattern: 3 generations per year, late July to August (2nd generation larvae of the year). Continuous drought followed by high temperatures after rain will aggravate the damage.
Control:
①Remove larvae that damage leaves by sticking them together during pruning;
②Spray insecticides to kill larvae
a. First choice of pollution-free pesticide: diflubenzuron No. 3 at 1000-1500 times dilution;
b. Second choice of low-toxicity pesticides: 1.2% nicotine-anabasine EC at 800-1000 times dilution, or 2.5% deltamethrin (Decis) at 1500-2000 times dilution;
c. Other pesticides: 40% chlorpyrifos at 1500 times dilution, or 40% monocrotophos at 1500-2000 times dilution.
2. Sophora inchworm (Semiothisa cinerearia)
Hosts: Chinese pagoda tree (Sophora japonica), dragon-claw pagoda tree (weeping pagoda tree)
Occurrence pattern: 4 generations per year, overwintering as pupae in shallow soil. Adults emerge in mid-April, eggs laid singly on the upper surface of leaves in sheet-like clusters. Larvae damage from early May to early October, with overlapping generations. Damage is generally heavier in early to mid-May, mid to late June, mid to late August, and early to mid-September. Damage is severe during drought with little rain, and light during prolonged overcast and rainy periods. When disturbed, larvae drop down on silk threads, hence the name "hanging ghost."
Control:
①Chemical control of larvae
a. First choice pesticide: 20% diflubenzuron No. 1 at 5000-8000 times dilution, or diflubenzuron No. 3 at 1500-2500 times dilution;
b. Second choice pesticide: Bt emulsion at 500-600 times dilution, or 1.2% nicotine-anabasine EC at 800-1000 times dilution;
c. Other pesticides: 2.5% deltamethrin at 1500-2000 times dilution.
②In winter, digging for pupae in the shallow soil layer under and around Chinese pagoda trees and in wall cracks is very effective for reducing the overwintering population density.
3. Ailanthus weevil (Eucryptorrhynchus brandti)
Hosts: tree of heaven (Ailanthus altissima), Ailanthus altissima 'Qiantou,' and red-leaf Ailanthus.
Occurrence pattern: 2 generations per year, overwintering as larvae or adults inside tree trunks or in soil. The following year from late April to early to mid-May, overwintering larvae pupate; adults emerge from June to July, with peak emergence in July. Larval damage begins in mid to late April; mid-April to mid-May is the damage period after overwintering-generation larvae emerge from dormancy the following year. Late July to mid to late August is the peak damage period for larvae hatched that year. Generations overlap considerably and are very irregular, with adults occurring even into October. Adults exhibit thanatosis (playing dead); after emerging from the emergence hole, they need supplementary nutrition and feed on tender shoots, leaves, and petioles. Adults begin laying eggs after about 1 month of damage; the egg stage lasts 7-10 days. Larval hatching begins in early to mid-May in the first half of the year and from late August to early September in the second half. After hatching, larvae first feed on the cortex in the phloem beneath the bark surface, boring and causing damage; once slightly larger, they bore into the xylem and continue tunneling. The bore holes are circular; after maturing, they pupate within tunnels in the xylem, with a pupal stage of 10-15 days. Affected trees often exhibit gumming. Also occurring together with this pest is the "grooved snout weevil" (Eucryptorrhynchus chinensis).
Newly transplanted tree of heaven, Ailanthus altissima 'Qiantou,' and red-leaf Ailanthus are particularly susceptible to this pest during the post-transplant recovery period when growth vigor is weak.
4. Crape myrtle felt scale (Eriococcus lagerstroemiae)
Hosts: crape myrtle (Lagerstroemia indica), pomegranate, and privet (Ligustrum)
Occurrence pattern: August-September is the peak period for the 2nd generation nymphs' occurrence and damage.
Control: ①Protect natural enemies: ladybugs, green lacewings, aphelinid wasps, and encyrtid wasps; ②In winter, scrub or spray with 5-degree Baumé lime sulfur mixture; ③Apply pesticide during the damage period: bury "Dihaiping" (1.5-3.0 g/sq m) at the roots, or spray 40% methidathion at 1500-2000 times dilution or 25% wax scale control agent at 1000-1500 times dilution.
5. Meadow moth (Loxostege sticticalis)
Hosts: turfgrass
Control: Can be controlled with trichlorfon, deltamethrin, or fenvalerate.
In addition, red spider mites and turfgrass armyworms are still occurring; continue control measures.
September
1. Pay attention to the tending and management of all types of garden plants, especially during the autumn drought period and the post-bloom period of flowering plants; take corresponding water and fertilizer measures to lay a good foundation for enhancing plant growth vigor in autumn and nutrient storage during dormancy.
2. September is the peak period for the occurrence and damage of autumn pests and diseases. Close monitoring and timely control should be carried out to minimize the density of all types of pests and diseases.
3. Carry out greening maintenance and sanitation cleanup work in parks, roads, plazas, and construction sites.
[Main diseases]
1. Turfgrass leaf spot (bankruptcy spot)
Symptoms: Turfgrass develops wilting patches of varying sizes; grass plants fade to yellowish-brown; roots, crown, and root collar turn dark brown; the outer cortex of vascular bundles rots; entire plants die.
Control methods:
①64% ferrous ammonium sulfate at 600-700 times dilution; ②70% mancozeb at 500-600 times dilution; ③50% meimycin at 500-600 times dilution; ④90% fosetyl-aluminum at 500-600 times dilution.
2. Turfgrass brown patch (Rhizoctonia solani blight)
Symptoms: Infects leaves, sheaths, and stems of turfgrass plants, causing leaf rot, sheath rot, and stem base rot. Individual leaves develop brown spindle-shaped or elongated lesions 5-50 mm long, initially grayish-blue, later dark brown; in severe cases, lesions encircle the stem. Entire leaves become water-soaked and rot; tillers of diseased plants mostly die. Turfgrass develops nearly circular dead grass patches of 1-2 m; during warm and humid conditions, a "smoke ring" appears, which later becomes a "frog-eye" pattern with green centers and yellow-brown margins.
Control: ①70% mancozeb at 500-600 times dilution; ②70% thiophanate-methyl at 600-700 times dilution; ③50% meimycin at 500-600 times dilution; ④72.2% propamocarb aqueous solution at 800 times dilution + 50% thiram at 800 times dilution for drenching.
3. Rose black spot
Control method: Spray 80% zineb at 600 times dilution or 50% carbendazim at 500-600 times dilution.
4. Cherry brown spot
Control method: Spray 58% ridomil MZ at 500 times dilution or 50% kasugamycin-copper at 1000 times dilution.
5. Euonymus japonicus wilt disease
Control method: Drench with 50% zineb wettable powder at 500 times dilution.
[Main insect pests]
1. Apple prominent moth (Phalera flavescens): commonly known as boat-shaped caterpillar
Hosts: flowering almond (Prunus triloba), crabapple, cherry blossom, cherry, peach, elm, papaya, and many other plants.
Pattern: 1 generation per year; adults emerge in July; larvae hatch and cause damage from August to October. In late autumn, they enter the soil to pupate and overwinter. Larvae have 5 instars, exhibit gregarious feeding, drop on silk threads, and feign death; they feed day and night with a large appetite, and can strip an entire branch or even an entire tree of leaves overnight.
Control: ①Spray 10% tebufenozide suspension at 1500-2000 times dilution; ②Spray 2.5% deltamethrin EC at 1000-1500 times dilution; ③Spray 20% fenvalerate EC at 1500-2000 times dilution.
2. Slug moths (Eucleidae)
Hosts: In addition to damaging Rosaceae plants generally, they also damage London plane, walnut, jujube, persimmon, pomegranate, ash, mulberry, and more than 100 other plant species.
Pattern: This pest has 1 generation per year; adults emerge in July; larvae hatch and cause damage from August to October, feeding exclusively on leaves, initially in mesh-like patterns, later causing notches, holes, and eventually stripping the leaves completely.
Control: ①Spray 20% diflubenzuron at 5000-6000 times dilution, or diflubenzuron No. 3 suspension at 2000-2500 times dilution; ②Spray Bt emulsion at 500 times dilution; ③Spray 2.5% deltamethrin at 1000-1500 times dilution, or 20% fenvalerate EC at 1500-2000 times dilution, or 10% tebufenozide suspension at 1000-2000 times dilution, or Sulibao suspension at 800-1000 times dilution. ④Protect natural enemies: ichneumon wasps, braconid wasps, assassin bugs, and praying mantises.
3. Aromatic goat moth (Cossus cossus)
Control: Since larvae crawl out of tree holes in late September to enter the soil and spin cocoons to overwinter, a ring of "Chuchongjing" powder can be scattered on the soil surface around the trunk base to kill larvae entering the soil (but pay attention to environmental safety; do not let poultry, pigeons, or pets come into contact and be poisoned).
4. Japanese wax scale (Ceroplastes japonicus)
Hosts: London plane, Euonymus japonicus, etc.
Control: Spray 40% methidathion at 1000-1500 times dilution.
5. Others
(1) Various longhorn beetle larvae
September is another peak period for boring damage by most longhorn beetle larvae. There are generally two types of damage:
①Shallow-layer damage - larvae hatched in the current year bore and damage within the phloem; no obvious frass holes on the tree surface, and no frass on the ground
②Deep-layer damage - larvae hatched last year or the year before bore and damage within the xylem; obvious frass holes on the trunk, with accumulated frass around the holes or scattered frass and wood shavings on the ground.
Control: For shallow-layer damaging larvae, brush the trunk with a relatively strong systemic 40% monocrotophos concentrated solution at 100-500 times dilution. For deep-layer damaging larvae, after clearing frass from the frass holes, insert and plug "zinc phosphide" poison sticks, seal with clay, forming a sealed "gas chamber" so that the poison sticks, after absorbing moisture, release "phosphine" gas that penetrates everywhere inside the trunk to fumigate and kill the larvae, with good results.
(2) Leaf-feeding pests: 4th generation larvae of Sophora inchworm, poplar lappet moth larvae, hawk moth larvae, etc.
Control: Spray diflubenzuron No. 3 suspension at 2000-2500 times dilution, or Bt emulsion at 500 times dilution, or 2.5% deltamethrin at 1500-2000 times dilution.
(3) Piercing-sucking pests: red spider mites, scale insects, thrips, whiteflies, aphids, etc.
Control: Spray ①15% fenbutatin oxide at 1000-1500 times dilution (red spider mites); ②40% methidathion at 1500-2000 times dilution (scale insects); ③20% buprofezin at 1000-1500 times dilution (whiteflies, psyllids); ④10% imidacloprid at 1000-2000 times dilution (whiteflies, aphids); ⑤1.2% nicotine-anabasine EC at 800-1000 times dilution (thrips, aphids).
For the control of piercing-sucking mouthpart pests, regardless of whether the affected plant is a tree, flowering shrub, herbaceous flower, potted flower, or perennial flower, soil application of "Temik" technical material at 3-5 g/sq m, or at 2-3 g per cm of trunk diameter at breast height, gives good results and long residual activity.
October
Recently, temperatures have dropped significantly, and various pests and diseases on garden plants have decreased somewhat, but some pests and diseases will continue to cause damage. This month's control focus should be on aphids and leafhoppers.
Now, some predictions about pests and diseases that will occur in the near future. Aphids: Autumn is the second season of massive aphid reproduction. In September, they were found on many plants in various green spaces in the city, with an upward trend. In October, attention should be paid to control to prevent massive outbreaks. Spray control can use 10% imidacloprid (aphid all-kill) at 1500-2000 times dilution and other pesticides.
Leafhoppers
Various leafhoppers such as the tea leafhopper and small green leafhopper in green spaces cause serious damage to garden plants such as ornamental peach, plum blossom, and cherry blossom, causing leaves to turn pale, premature defoliation, and spreading viral diseases, leading to leaf curling. Leafhoppers will lay eggs and overwinter in mid to late October; timely control should be carried out to reduce overwintering pest sources. Control can use 10% imidacloprid (aphid all-kill) at 1500-2000 times dilution or 20% fenvalerate at 3000-4000 times dilution for spray control.
Large bagworm (psyshide moth)
In June of this year, small bagworms caused relatively severe damage on camphor trees; large bagworms cause damage somewhat later than small bagworms and will continue until October, overwintering as mature larvae. Compared with small bagworms, large bagworms' bags lack small twig fragments. In various green spaces and street trees, quite a few camphor trees are still being damaged. Attention should be paid to early control; Bt or trichlorfon can be sprayed, and when spraying, the insect bags must be thoroughly penetrated.
In October, attention should also be paid to the damage from Clostera anachoreta, Micromelalopha troglodyta, turfgrass rust, and other pests and diseases, and overwintering eggs and pupae on branches should be removed to reduce overwintering pest sources for the coming year.
November
I. Clean the garden: The pathogens (fungi) or overwintering eggs of most garden pests and diseases overwinter in fallen leaves, dead branches, or weeds within the garden, and become active again when conditions are suitable the following year. Therefore, thoroughly clearing and destroying fallen leaves, dead branches, and weeds in the garden during winter and improving sanitation can greatly reduce various pest and disease sources.
II. Prune off diseased and pest-infested branches and leaves: Winter pruning is one of the important steps in garden management. In conjunction with winter pruning, focus on cutting off pest- and disease-infested branches and leaves. Pruned diseased and pest-infested branches and leaves should be promptly cleaned up and transported out of the garden for centralized disposal. Carry out heavy pruning on all Erythrina genus plant branches and leaves, completely removing 1-2 year old branches; on branches and leaves that are about to be pruned or have already been pruned, spray broad-spectrum, low-toxicity, highly penetrative, and highly effective insecticides such as 16% Chongxianqing at 100 times dilution onto the surface of branches and leaves to prevent pests from emerging and migrating; pile the sprayed branches and leaves in a nearby open area, spray an appropriate amount of diesel and burn them; where fire use is not suitable, seal the pesticide-treated branches and leaves in plastic bags to suffocate the pests.
III. Whitewash trunk and branches: Whitewashing trunk and branches can not only effectively prevent winter frost damage to trees and improve disease resistance, but also destroy overwintering sites for pests and diseases, serving the dual purpose of frost protection and pest control. The whitewash formula is: quicklime 3 parts, sulfur 0.5 parts, salt 0.5 parts, white latex appropriate amount. First dissolve the lime in water, filter out residue and gravel to make lime milk, then add latex, then add sufficient water, finally add sulfur and salt, and stir evenly.
IV. Winter plowing and deep turning: Winter plowing and deep turning can cause mechanical injury to underground pests lurking in the soil, and after exposure to the surface, they can be pecked and eaten by birds and other natural enemies; if necessary, manual capture and killing can also be carried out. In addition, deep turning buries pathogens from the surface soil into deep soil layers, and brings pathogens from deep soil layers to the surface, destroying the suitable living environment for pests and diseases and effectively controlling their occurrence.
V. Chemical control
(1) Common pests and diseases still occurring and causing damage in winter
Although most flower pests and diseases enter overwintering (or dormancy) in winter, due to the influence of abnormal warm winter climate and the strong adaptability of some pest and disease species, some pest and disease species continue to be active in winter, damaging garden plants. In our city, the main pest and disease species that can still damage garden plants in winter include the mulberry white caterpillar, some scale insects, some aphids, black spiny whitefly, Ficus thrips, termites, longhorn beetles, sooty mold, and osmanthus leaf spot. Timely targeted control should be carried out according to their occurrence and damage characteristics to control their damage.
1. On most greening plants, scale insects and sooty mold occur together. Scale insects are relatively common, with many species and comparable damage; on some tree species, insect bodies even cover stems, branches, and leaves entirely, seriously affecting the growth and appearance of greening plants. Sooty mold is one of the most important diseases on garden plants in the central urban area of Quanzhou, occurring very commonly, mainly damaging leaves, tender branches, and flowers of plants. The affected parts form sooty mold layers; in severe cases, the entire leaf is covered with a thin layer, inhibiting photosynthesis, weakening plant growth vigor, and seriously affecting the ornamental effect of garden plants.
Control measures: Spray with insecticides such as methidathion, omethoate, dichlorvos, and phoxim mixed with fungicides such as Chuangtan Meiyanjing, Tanchuang Kuiyanling, Anna garden plant cleaning agent, and thiophanate-methyl.
2. On Ficus genus plants such as Ficus microcarpa 'Golden Leaves,' weeping fig, Ficus macrophylla, and Ficus microcarpa, the mulberry white caterpillar and Ficus thrips occur and cause damage in large numbers. The larvae of the mulberry white caterpillar feed on leaves and tender shoots; young larvae bite and eat leaf mesophyll, while older larvae devour leaves. Because the larvae have a mimicry phenomenon, they are not easily found and can easily cause major damage. The nymphs and adults of Ficus thrips rasp and suck the sap of host tender leaves and young buds, causing purple-red-brown spots of varying sizes, withered bud tips, and leaves folding toward the upper surface along the midrib, forming dumpling-shaped galls.
Control measures: Spray with imidacloprid, fenpropathrin, deltamethrin, and other pyrethroids mixed with organophosphorus pesticides such as phoxim.
3. On plants such as Bauhinia, Cinnamomum pedunculatum, and golden shower tree, the black spiny whitefly occurs and causes damage. Black spiny whitefly gathers and pierces-sucks the sap of plant leaves (leaf undersides), fruits, and tender branches. Affected leaves show chlorotic yellow-white spots; in severe occurrences, spots expand into patches, and then the entire leaf turns pale, causing defoliation and dead shoot tips.
Control measures: Spray buprofezin (mieshijing), bifenthrin, and other pesticides.
4. On woodland tree species such as willow, longan, Syzygium hainanense, Ficus microcarpa, and Taiwan acacia, damage by termites in winter is relatively severe; willow, Italian poplar, etc., are relatively severely damaged by longhorn beetles. Termites often build nests in the soil, feeding on plant roots and stems, and construct mud sheets on trees, gnawing bark, and can also invade the xylem through wounds to cause damage. Affected plants grow poorly or even die entirely. Longhorn beetle larvae bore into and feed on the main trunk and branches, creating irregular tunnels, destroying the transport of nutrients and water in the tree body, leading to weakened tree vigor and, in severe cases, death of the entire tree.
Control measures: (1) Around nursery sites where termite damage occurs, dig trap pits (depth over 50 cm), place bait favored by termites such as fresh pine wood, sugarcane stems, sugarcane peel, and eucalyptus bark as attractants; after large numbers of termites are attracted to the trapping point, spray infectious termite-killing agent to achieve the goal of killing large numbers of termites. (2) For termites damaging trees, spray chlorpyrifos at 1000 times dilution or deltamethrin at 500 times dilution onto the mud lines or mud sheets, with the mud lines or mud sheets thoroughly moistened but the soil not falling off as the appropriate level; do not first remove the mud lines or mud sheets before spraying. (3) On plant branches and trunks where longhorn beetle damage occurs, first use tweezers or a grafting knife to clean out frass holes with fresh frass discharge, then insert 56% aluminum phosphide tablets (broken into small pieces of 0.2-0.3 g, inserting one small piece into each bore hole) or zinc phosphide poison sticks, and seal other frass holes with clay; or use a veterinary syringe to inject 80% dichlorvos at 20 times dilution, 50% fenitrothion at 50 times dilution, or 50% monocrotophos EC at 2-5 ml, then seal the hole with mud.
5. Plants such as oleander, red mulberry, pittosporum, Magnolia denudata, ornamental peach, red-leaf plum, pomegranate, hibiscus, plum blossom, and camellia are susceptible to aphid damage in winter. Aphid adults and nymphs gather on plant tender leaves and young buds to pierce-suck sap, causing leaves to turn yellow and curl; their excrement induces sooty mold, affecting growth and ornamental value.
Control measures: Spray pirimicarb, menazon, alpha-cypermethrin, and other pesticides.
6. Osmanthus is prone to leaf spot disease in winter. Osmanthus leaf spot damages leaves; lesions are yellow-brown, gray-brown to gray-white, with dark brown margins, nearly circular or irregular in shape, with a clear boundary between the margin and healthy tissue. In severe cases, lesions interconnect to form large dead spots, with the dried area reaching 1/3 to 1/2 of the leaf; the dead parts become brittle, and leaves curl, crack easily, and fall off.
Control measures: Spray with propiconazole, carbendazim, or benomyl, once every 10 days, for 2 to 3 consecutive applications.
7. Pest and disease control for Erythrina genus plants: Spray pesticides such as Haoniandong and imidacloprid.
(2) Overwintering pest and disease control
During the dormancy period, the overwintering sites and early spring initial outbreak periods of pests and diseases are relatively concentrated, with uniform instars, and this is the weakest period of the year, facilitating concentrated control. When plants enter dormancy, their tolerance to pesticides is strong; after winter pruning, plants have fewer branches and leaves and strong air permeability, making spraying easy to apply evenly and thoroughly, saving pesticide and giving good results. Therefore, using the favorable opportunities of winter and early spring to carry out comprehensive chemical control on garden plants gives the best results. Specific control measures are as follows:
(1) In the late dormancy period of plants, spray crystal lime sulfur mixture at 150-250 times dilution and scale-killing machine oil emulsion at 30-50 times dilution. Adding organophosphorus pesticide at 1500-2000 times dilution to the machine oil emulsion can significantly improve pest and disease control results.
(2) Root application of carbofuran, Temik, and other pesticides has good effects on reducing underground pests, trunk-boring pests, and piercing-sucking pest overwintering sources and damage the following year.
December
December: Low temperatures; begin winter maintenance work.
1. Winter pruning: Prune some evergreen trees and shrubs.
2. Eliminate overwintering pests and diseases.
3. Prepare for next year's adjustment work: After deciduous plants lose their leaves, observe the maintenance area and map out the positions to be adjusted.