Pest and Disease Control for Pomegranate Bonsai: Controlling the Crape Myrtle Mealybug

The crape myrtle mealybug, also known as the pomegranate felt scale, is one of the main pests harming pomegranate bonsai and is also a common pest of crape myrtle bonsai.

I. Morphological characteristics. Adult: The female adult is flat, oval, 2-3 mm long, dark purplish-red. When fully mature, it is enclosed in a white felted cocoon, appearing like a white grain of rice; the male is about 1 mm long, purplish-red, with 1 pair of wings. Egg: purplish-red, round. Larva: purplish-red, oval, with spines along the body margin. Pupa: The male pupa is long-oval, purplish-brown, enclosed in a sac-like cocoon.

II. Life habits and damage symptoms. The number of generations of the crape myrtle mealybug per year varies by region. It overwinters as fertilized females, nymphs, or eggs in cracks in the branches and trunk. Each year, early June to mid-July and September are the peak hatching periods. This pest often gathers at the base of the main veins of leaves on small branches, at bud axils, and on tender shoots, piercing and sucking sap and weakening the tree's vigor. It also secretes large amounts of honeydew, which induces severe sooty mold, turning leaves and small branches black and causing them to lose their ornamental value.

III. Control methods. 1. Before bud break in spring, spray 3-5 degrees Baume lime sulfur mixture, and combine with pruning to remove severely infested branches. 2. The crape myrtle mealybug has many natural enemies. Among predatory natural enemy insects, the red-spotted ladybird beetle is the main one, and it can prey on more than 50 crape myrtle mealybugs per day. It can be introduced and reared from research institutions. 3. Strengthening quarantine of bonsai pests is an effective measure to prevent and limit the spread of the crape myrtle mealybug. 4. During the nymph hatching period, the crape myrtle mealybug has poor pesticide resistance, making this the key period for control. Spraying 40% dimethoate or 40% omethoate at 1000 times dilution, or 2.5% deltamethrin at 2500 times dilution, or 20% fenvalerate-malathion emulsifiable concentrate at 2500 times dilution can achieve good control results. During the nymph and adult stages, the crape myrtle mealybug's pesticide resistance increases, and general spraying has little effect, while drenching or root application of systemic insecticides is clearly effective. When the potting soil is dry, drench with 40% omethoate at 1000 times dilution, using the same amount as the irrigation water, and the effect becomes obvious after 7-10 days. For burying granules, dig a small ring trench 1-2 cm deep around the root zone in the pot, evenly scatter in the granules, then cover with soil and water thoroughly, and after 7-10 days good results can be obtained.

It is worth noting that for pomegranate bonsai, the use of fenitrothion (sumithion, MEP) is strictly prohibited to avoid phytotoxicity.

Pest and Disease Control for Pomegranate Bonsai

I. Morphological characteristics. Adult: The female adult is flat, oval, 2-3 mm long, dark purplish-red. When fully mature, it is enclosed in a white felted cocoon, appearing like a white grain of rice; the male is about 1 mm long, purplish-red, with 1 pair of wings. Egg: purplish-red, round. Larva: purplish-red, oval, with spines along the body margin. Pupa: The male pupa is long-oval, purplish-brown, enclosed in a sac-like cocoon.

II. Life habits and damage symptoms. The number of generations of the crape myrtle mealybug per year varies by region. It overwinters as fertilized females, nymphs, or eggs in cracks in the branches and trunk. Each year, early June to mid-July and September are the peak hatching periods. This pest often gathers at the base of the main veins of leaves on small branches, at bud axils, and on tender shoots, piercing and sucking sap and weakening the tree's vigor. It also secretes large amounts of honeydew, which induces severe sooty mold, turning leaves and small branches black and causing them to lose their ornamental value.

III. Control methods. 1. Before bud break in spring, spray 3-5 degrees Baume lime sulfur mixture, and combine with pruning to remove severely infested branches. 2. The crape myrtle mealybug has many natural enemies. Among predatory natural enemy insects, the red-spotted ladybird beetle is the main one, and it can prey on more than 50 crape myrtle mealybugs per day. It can be introduced and reared from research institutions. 3. Strengthening quarantine of bonsai pests is an effective measure to prevent and limit the spread of the crape myrtle mealybug. 4. During the nymph hatching period, the crape myrtle mealybug has poor pesticide resistance, making this the key period for control. Spraying 40% dimethoate or 40% omethoate at 1000 times dilution, or 2.5% deltamethrin at 2500 times dilution, or 20% fenvalerate-malathion emulsifiable concentrate at 2500 times dilution can achieve good control results. During the nymph and adult stages, the crape myrtle mealybug's pesticide resistance increases, and general spraying has little effect, while drenching or root application of systemic insecticides is clearly effective. When the potting soil is dry, drench with 40% omethoate at 1000 times dilution, using the same amount as the irrigation water, and the effect becomes obvious after 7-10 days. For burying granules, dig a small ring trench 1-2 cm deep around the root zone in the pot, evenly scatter in the granules, then cover with soil and water thoroughly, and after 7-10 days good results can be obtained.

It is worth noting that for pomegranate bonsai, the use of fenitrothion (sumithion, MEP) is strictly prohibited to avoid phytotoxicity.

At present, there are many kinds of flowers in our country. Which varieties actually have good market prospects for development? Relevant experts believe that the flower market has the following trends:

Flower shape interchange. That is, changing traditional flower shapes, with large flowers becoming small flowers and small flowers becoming large flowers, giving people a fresh new feeling and greatly increasing interest. For example, crabapple flowers grafted onto papaya have a diameter more than 1 times larger than ordinary crabapple flowers; the diameter of miniature potted bowl lotus is only half that of pond-grown bowl lotus.

Multiple colors in one flower. That is, flowers changing from one color or two colors to multiple colors. For example, lotus originally had only white and pink, but now there are red, peach, purplish-red, light yellow, orange, and many other colors; ordinary sophora flowers are white, while the new fragrant sophora tree varieties now have yellow, red, and many other colors.

Sculpted bonsai. Such as lingzhi bonsai, edible cactus bonsai, ginkgo bonsai, pomegranate bonsai, jujube bonsai, peach bonsai, apple bonsai, and other sculpted bonsai flowers.

Ground planting changed to pot planting. Such flowers include miniature potted Chinese rose, potted pomegranate, potted peach blossom, and other flower varieties, as well as potted lotus (bowl lotus, water lily) and other varieties changed from pond planting to pot planting.

Abnormal flowering periods. This can be divided into 3 situations: first, flowering twice or more in 1 year; second, extending the normal flowering period; third, off-season flowering, that is, using advanced science and technology to advance or delay the flowering period.

Overwintering Care and Management of Flowering Bonsai

Low temperatures and frosty weather in winter can pose a serious threat to flowers and trees. To help flowers and trees overwinter safely, the first thing is to follow the principle of "do not bring in during winter, do not take out during spring." "Do not bring in during winter" means that when the weather has just turned cold and there is no frost, for most flowers, do not rush to move them indoors. "Do not take out during spring" means that when the weather turns warm, do not rush to move them outdoors; wait until the last late frost of spring has passed and the weather has fully improved before starting to move them outdoors.

Five key elements and precautions for overwintering care and management of flowering bonsai

I. Understand the cold tolerance temperatures of flowers:

Different cold protection and warmth measures should be taken according to the different low-temperature tolerance of different flowers and trees, either moving the flowers and trees directly indoors, covering the flower pots with plastic film, directly slipping plastic bags over the flowers and trees, or temporarily setting up a simple small greenhouse for insulation. For flowers and trees with strict light requirements, place them on an indoor windowsill or in a sunny spot near a windowsill; for those with less strict light requirements or that can tolerate shade, place them in a shaded, cool place without light, but in all cases pay attention to ventilation and air permeability. It is best to open windows for ventilation at noon on sunny days, but do not let cold wind blow directly on the flowers and trees.

1. For flowers that can tolerate cold and low temperatures, cold temperatures (5-12°C, below 5°C), such as pomegranate, Chinese rose, wintersweet, osmanthus, palm, Chaenomeles speciosa, and crape myrtle, they can be placed in an outdoor courtyard or a sunny spot on a balcony.

2. For flowers that need to be kept at moderate temperatures (12-20°C), such as Michelia alba, camellia, azalea, Michelia figo, clivia, fuchsia, and begonia, they must be moved indoors before the temperature drops to 10°C.

3. For flowers that can grow normally only at high temperatures (18-30°C), such as: Aglaia odorata, hibiscus, jasmine, croton, narcissus, epiphyllum, Epiphyllum hybrid, cactus, Pachira macrocarpa, spider plant, pothos, hibiscus, poinsettia, begonia, jasmine, Monstera deliciosa, cactus ball types, and aloe, they must be moved indoors before the temperature drops to 12°C.

After plants are moved indoors, their placement also requires attention. They should be placed in a sunny, warm spot. Sun-loving plants should be placed in front, and semi-shade-tolerant or shade-tolerant potted flowers should be placed behind, and the orientation should also be changed irregularly. In the first week, windows should be opened for ventilation to let the plants gradually adapt to temperature changes. Potted flowers moved indoors, for the sake of appearance and also to ensure effective absorption of nutrients.

For plants placed outdoors, wind barriers can be set up for cold protection. Common cold protection measures include mounding soil and covering soil around the roots and stems. Root and stem mounding means building a small mound of soil at the root collar of the tree to prevent low temperatures from freezing and damaging the root collar and tree roots, while also reducing soil moisture evaporation. For flowers such as peonies that are planted in the soil and cannot be moved indoors, a large basket can be turned over to cover the entire plant, and the basket can be coated with a layer of mud, similar to a warm and humid small greenhouse.

II. Pruning before overwintering:

Before potted flowers overwinter, they should be pruned and shaped in a timely manner to reduce nutrient consumption and reduce the indoor space they occupy during winter. For potted flowers moved indoors, pruning is essential both for appearance and to ensure effective absorption of nutrients. Cutting off dead leaves, overly dense branches, diseased and pest-infested branches, and weak branches can fully supply nutrients to effective branches and trunks, helping the potted flowers grow robustly and overwinter safely. For excessively elongated branches and trunks, pruning can be strengthened. Binding materials on bonsai that have been shaped for 1-2 years can be removed, or removed and then rebound, to prevent long-term binding at fixed positions from damaging the cambium of the branches and causing the branches and leaves to die. For tree stump bonsai placed on balconies, such as Chinese elm, Chinese wingnut, trident maple, banyan, Buddhist pine, Chinese juniper, and dragon juniper, necessary pruning must be carried out. For jasmine, crape myrtle, pomegranate, and others, pruning can be done in late autumn to reduce the plant's nutrient consumption in winter, promote greater nutrient storage in the potted flowers, and make them bloom more the following year. Dead branches, densely growing branches, diseased and pest-infested branches, overly old branches, and damaged branches can all be removed with a sharp knife or sharp shears; for those that bloom in spring, only appropriately thin out autumn shoots without flower buds; for those that bloom on current-year branches, pruning should be strengthened to promote new shoots and prepare for flowering the following year; for those that have been frost-damaged but still have some surviving parts, heavy pruning can be carried out, while strengthening fertilizer and water management to help the flowers and trees quickly recover their growth vigor.

III. Precautions for fertilizing during overwintering:

Apply fertilizer once before overwintering and water thoroughly. During overwintering, flowers generally should stop being fertilized. For flowers and trees in dormancy or semi-dormancy, fertilization should be stopped to avoid root rot, and fertilizing should wait until repotting in spring; for flowers and trees that bloom in autumn and winter or early spring, as well as those sown in autumn, thin fertilizer should be applied. To improve the cold resistance of flowers and trees, fertilization should be reduced in late autumn to prevent the stems and leaves of flowers and trees from growing tender and lowering cold resistance.

IV. Precautions for watering during overwintering:

In winter, flowers and trees grow slowly, their metabolism decreases, and most enter a dormant state, so water demand and evaporation are relatively reduced. The principle of watering is "better dry than wet," and never water before the potting soil is dry, especially for shade-tolerant flowers, and do not water too much, to avoid leaf drop, root rot, or death. Generally, it is best to water thoroughly only after the potting soil has dried out. The water temperature for watering is best close to room temperature, and warm water at 20-25°C can also be used to water flowers. Watering flowers with warm water will accelerate the decomposition of organic matter in the potting soil and promote the absorption of nutrients by root cells, thereby promoting flower growth. The best time to water is at noon when light is good. If using tap water to water flowers, it is best to store it for 1-2 days first and use it after the chlorine in the water has volatilized. At the same time, avoid watering flowers with water containing soap or laundry detergent. Along with watering, a damp cloth can be used to carefully wipe dust off the leaf surfaces.

V. Precautions for ventilation of indoor flowers:

Pay attention to regular ventilation, preferably on sunny days when there is sun, or at noon when the temperature is higher. When ventilating and exchanging air, also be sure not to let cold wind blow directly on the plants, to avoid adverse reactions.

VI. Pest and disease control during overwintering:

For flowers and trees whose leaves are prone to pests and diseases, such as begonias, roses, and camellias, collect and burn the dead branches and fallen leaves under the plants, which can reduce the occurrence of diseases the following year. At the same time, spray carbendazim for sterilization and disinfection. For ** disease, rust disease, and primrose gray mold, respectively use triadimefon or thiophanate-methyl for timely control. For flower species on which aphids often appear on potted plants when ventilation is poor, such as Michelia alba and Aglaia odorata, imidacloprid can be used for control. For scale insects, of course, the highly targeted Jiebijiezhi must be used for control. Common diseases of flowers and trees in winter include powdery mildew and sooty mold, and common pests include aphids, whiteflies, and scale insects. Effective measures should be taken to control them during the dormant period, so as to reduce the occurrence of pests and diseases in the coming spring.

Next spring, generally from the Spring Equinox to Qingming, overwintered flowers can be moved outdoors one after another, and fertilizer and water can be applied, such as bio-organic fertilizer, Huangyebijiezhi, and trace element water-soluble fertilizer, so that the flowers grow normally in spring.