Applying nitrogen fertilizer properly to effectively prevent and control plant pests and diseases
Nitrogen fertilizer is one of the fertilizers we use more commonly. In fact, many studies and practices have shown that rational fertilization can prevent and control crop pests and diseases. In the process of fertilizing, it is possible both to apply fertilizer and to avoid polluting the environment, so it can be said to achieve multiple benefits at once. So how exactly can nitrogen fertilizer be used to prevent and control plant pests and diseases?
Tree peony
1. Ammonium bicarbonate, ammonia water and other ammonium-form nitrogen fertilizers have relatively strong volatility and have a certain stimulating, corrosive and fumigating effect on pests, especially with better results against pests that are small in size and weak in endurance, such as red spider mites, aphids and thrips. Application method: spray evenly with a 1% ammonium bicarbonate or 0.5% ammonia water solution, once every 5-7 days, for 2-3 consecutive sprays.
2. Urea has the effect of destroying insect chitin. The "urea-washing powder mixture" made by mixing urea, washing powder and water at a ratio of 4:1:400 has a good control effect on many pests harming cotton, vegetables and flowers, such as aphids, cabbage caterpillars and red spider mites.
3. When wheat rust occurs sporadically, spraying with 50% fresh urine or a 3% ammonium sulfate aqueous solution gives good results.
Winter prevention and control of plant pests and diseases
Winter prevention and control of plant pests and diseases -- In winter, pests mostly overwinter as eggs, larvae, cocoons or adults (scale insects) in soil, dead branches and fallen leaves, weeds, bark, cracks, leaf axils, branches and trunks; pathogens mostly overwinter as mycelium or spores in diseased plant residues and in soil. For example, leafhoppers lay eggs on the branches of sweet osmanthus, Cinnamomum burmannii and camphor trees to overwinter (there is a white substance at the egg-laying site), and the branches above that site die; the small-leaf banyan psyllid overwinters as nymphs and eggs in leaf axils. These overwintering pest and disease bodies and overwintering sites should be removed in time.Dead branches and fallen leaves and weeds should be cleared away; diseased and pest-infested branches and overlapping branches should be pruned out. This can directly eliminate a large number of overwintering pests and pathogens, improve the ventilation and light conditions of the plants, and strengthen the trees' vigor the following year; manually remove cocoons, egg masses and leaf rolls, and scrape off overwintering scale insects; plow the soil and expose it to the sun to reduce overwintering pests and diseases in the soil; at the same time, promptly carry out control of trunk-boring pests.
Trunk whitewashing should be carried out after leaf fall and before the soil freezes (December). This can not only kill pests and diseases overwintering on the trunk, but also effectively reduce freezing damage. The whitewash material is quicklime, sulfur (or lime sulfur mixture), water and salt; the whitewashing height is 1.1 m.
In winter, attention should also be paid to freeze protection. Freezing damage is caused by a sharp drop in air temperature, which leads to the appearance of highly permeable non-lipid gaps on the plant protoplast membrane, leakage of intracellular substances and cell death. Young shoots that emerge in early winter can be pruned off to promote lignification of the branches and accumulation of nutrients and improve cold resistance; stop applying nitrogen fertilizer to trees, and appropriately apply some phosphorus and potassium fertilizer; spray antifreeze agents to enhance the plants' freeze resistance and reduce the mechanical damage to the membrane system caused by the formation of ice crystals in the protoplast at low temperatures; mounding soil around the root collar can prevent freezing injury to the root collar and roots, and can also reduce evaporation of soil moisture; for valuable cold-sensitive tree species, windbreaks can also be set up on the windward side of the trees.
Prevention and control of pests and diseases of palm family plants
Most palm family plants originate from the hot, humid tropical and subtropical regions, where the climate is very suitable for the breeding and reproduction of pests and diseases. With the continuous expansion of plant production and introduction areas, the types of pests and diseases and the degree and scope of their damage have also gradually increased, and control has become increasingly complex, becoming a major problem that cannot be ignored in palm cultivation and management. On the basis of previous research results, a superficial discussion is now presented on the common and relatively seriously harmful pests and diseases of palms in the Pearl River Delta region of Guangdong and their control methods.
I. Main diseases:
1. Heart rot:It harms many palm plants, mainly Christmas palm, bottle palm, red palm, areca palm, fishtail palm, coconut palm, foxtail palm, etc.
Control method: Eradicating diseased plants and burning or deeply burying them is one of the most effective control methods. After eradicating diseased plants, the surrounding environment (including the plants) should also be sprayed with 1% Bordeaux mixture for protection. The degree of harm of this disease is quite great, and once neglected, it will cause losses of varying degrees. The key to this disease lies in "prevention". From March to June each year, spray once a week with 65% zineb at 500 times, or amobam at 300 times, and strengthen fertilizer and water management, control moisture, and do not apply nitrogen fertilizer disproportionately, so as to prevent scale insect damage.
2. Trunk cracking disease:It mainly harms single-trunk plants, such as royal palm, queen palm and other common palm family plants.
Control method: Mechanical damage to the trunk should be prevented. For trees that have already developed the disease, strengthen fertilizer and water management, apply less chemical fertilizer and more organic fertilizer, and prevent drought and waterlogging. Surgical treatment can be carried out on the trunk: use a small knife to scrape the diseased tissue clean, apply 1% HgCI or potassium permanganate to the cut for disinfection, then apply metalaxyl or Bordeaux paste. After three to five treatments, seal the wound with glass glue or cement slurry.
3. Root rot:It mainly harms Christmas palm, Washington palm, etc., causing root tips to turn black and rot, leading to plant death.
Control method: In control, the main focus should be on "prevention". In cultivation, ensure good soil drainage, no water accumulation, and lower the groundwater level as much as possible. Chemical control includes drenching roots with metalaxyl at 500-700 times or carbendazim, or adjusting soil pH, etc.
4. Leaf spot:It mainly harms royal palm, short-spike fishtail palm, false betel nut palm, areca palm, three-medicine betel nut palm, Phoenix date palm genus, queen palm, Christmas palm, etc.
Control method: First prune off diseased leaves, appropriately increase the application of phosphorus and potassium fertilizer, and spray the leaf surface with 1% Bordeaux mixture, zineb at 500-700 times, copper oxychloride at 800-1000 times, or 50% captan at 300-500 times, once a week for several consecutive weeks.&bsp;
5. Anthracnose:It mainly harms false betel nut palm, royal palm, queen palm, fishtail palm, Phoenix date palm genus, Christmas palm, etc.
Control method: First strengthen fertilizer and water management to enhance the disease resistance of the plants. In the early stage of the disease, spray carbendazim at 500 times, 50% carbendazim at 800 times, 75% chlorothalonil at 500 times, copper oxychloride at 600-800 times, zineb at 500 times, thiram at 800 times, etc., for several consecutive applications.
II. Main insect pests:
1. Red-striped palm weevil:It mainly harms the Phoenix date palm genus. Both larvae and adults cause damage, with the most serious being dense boring by larvae; the larvae bore from the inner side of the leaf sheath all the way into the trunk, causing plant death.
Control method: This pest must be detected early. Adults can be captured when they emerge, or 80% dichlorvos at 600 times can be sprayed to kill adults. For larvae, 90% trichlorfon, 80% dichlorvos at 200-300 times plus methamidophos at 500 times can be sprayed on the tree trunk, and cotton dipped in high-concentration dichlorvos can be inserted into the insect's frass holes and sealed for fumigation for one week; repeating this several times can effectively control it. It is worth noting that this pest has already spread throughout most areas of this province (especially spreading in the Zhanjiang area, damaging royal palms), and there are even specialist breeders supplying edible larvae to restaurants.
2. Scale insects:They harm the leaves of areca palm, Arenga palm, rhapis palm, false betel nut palm, etc.
Control method: First prune off diseased and pest-infested leaves, then spray with pine-tar-alkali mixture at 16-20 times, 40% omethoate at 800 times, 44% aldicarb at 1000 times, 25% phosmet at 500 times with 1000 times machine oil added, or methidathion at 1000 times, once a month, for 3 consecutive sprays to achieve control results.
3. Moth and butterfly larvae:They mainly harm the leaves of areca palm, false betel nut palm, beautiful phoenix palm, Christmas palm, etc.
Control method: After pruning off diseased and pest-infested leaves, spray methamidophos at 500 times, dichlorvos at 900 times, or deltamethrin at 4000 times, for several consecutive applications.
4. Underground pests such as scarab larvae and mole crickets:They harm the roots of many plants, especially Christmas palm, Hawaii palm, three-medicine betel nut palm, etc.
Control method: Trichlorfon powder can be mixed into the soil. After the plants are planted, isofenphos-methyl at 500-800 times, 5% phoxim at 500 times, or carbofuran, Suhua 203, etc. can be drenched near the roots.
In addition, for the unfolded heart leaves harmed on coconut palm, Chinese fan palm, queen palm, royal palm, Washington palm, etc., control can include strengthening quarantine, spraying new seedlings comprehensively with pesticide, and regularly spraying dichlorvos at 600 times, deltamethrin at 800 times, etc.