Experience Sharing on Harmless Treatment of Pests and Diseases in Okra

It is understood that okra is a new type of health vegetable with relatively high nutritional value. After okra sets fruit, it is almost picked every day, and chemical control makes it very difficult to achieve high quality, safety and pollution-free products. For this reason, in view of the occurrence characteristics of okra pests and diseases and the production requirements for pollution-free agricultural products, the pest and disease control measures for okra are as follows:

1. Select good disease-resistant varieties and do a good job of seed treatment. Methods for disinfection and sterilization of seeds include hot water seed soaking, chemical seed soaking, high-temperature treatment, etc. Among them, hot water seed soaking is especially simple and easy to carry out, low in cost, and good in sterilization effect. Hot water seed soaking generally involves wrapping the seeds well with gauze before sowing (fill only a little over half the bag so the seeds remain loose). First soak the seeds in cold water for 10 minutes, then place them in warm water at 52--55℃ and soak for 10--20 minutes, while stirring quickly and continuously with a wooden stick so that the seeds are heated evenly. 2. Autumn plowing and winter irrigation. In fields with severe occurrence of pests such as cotton bollworm, thoroughly remove residual branches and fallen leaves at harvest, and carry out autumn plowing and winter irrigation, which can effectively reduce the pest population base and significantly lower the occurrence and damage of pests the following year. 3. Use insect-proof net covering. Using insect-proof nets to cultivate vegetables can basically avoid damage by medium and large pests and reduce the use of chemical pesticides. When choosing insect-proof nets, pay attention to selecting suitable specifications. It is generally considered that the more suitable specifications are 20--32 mesh, wire diameter 0.18 mm, width 1.2--3.6 m, white. During the period of isolation with insect-proof nets, uncover the nets as little as possible to prevent adult insects from flying in; promptly remove egg masses laid on the netting to prevent young larvae from boring into the net after the eggs hatch. 4. Trap and kill adult insects. For pests such as cotton bollworm and tobacco cutworm, frequency-vibration insect-killing lamps, sugar-vinegar basins, and poplar branch bundles can be used to trap and kill adults. Taro and corn trap strips can also be planted to trap and kill adults and reduce the number of eggs laid by adults. For pests such as aphids, their yellow-tropism habit can be used by using Linmao brand sticky insect boards, or by coating a layer of sticky gelatin on yellow plastic sheets, or by coating yellow cardboard with a layer of machine oil or sugar syrup plus the insecticide trichlorfon, etc., hanging 1 sheet at a certain interval at a height of about 70 cm, which can make winged aphids and others “walk right into the net”, killing pests without polluting the environment. 5. Manual control. Based on the characteristics that tobacco cutworm mostly lays eggs on the underside of leaves and at the forks of leaf veins and that newly hatched larvae gather to feed, during farming operations remove leaves with egg masses and with gathered larvae and treat them in a centralized way, which can greatly reduce pest density. When aphids occur sporadically in spots, the aphids on the underside of leaves can be wiped off by hand or the tender shoots can be removed. 6. Chemical control. Pests should be controlled early when they first appear. Biological pesticides and high-efficiency, low-toxicity, low-residue pesticides should be selected, and spraying should be done at the peak of young larvae. The application concentration and frequency must be strictly controlled, and harvesting should follow the pesticide safety interval. 1) Tobacco cutworm. Pesticides should be applied from the peak of egg hatching to the peak occurrence of young larvae. Pesticides can be selected from high-efficiency, low-toxicity, low-residue pesticides such as Aolü No. 1, Bacillus thuringiensis wettable powder, 5% teflubenzuron emulsifiable concentrate (Yitaibao), 5% flufenoxuron emulsifiable concentrate (Kasike), 20% tebufenozide suspension concentrate (Miman), 15% indoxacarb suspension concentrate, and 10% chlorfenapyr emulsifiable concentrate (Chujin). If control is carried out when the larvae are relatively old during the harvest period, only 15% indoxacarb suspension concentrate at 3750 times dilution, or 20% tebufenozide suspension concentrate at 1500-2000 times dilution, may be used, with an effect of more than 90%, and it can also control cotton bollworm at the same time. When spraying, the droplets should be fine and the application should be uniform and thorough. The safety interval is 3 days. 2) Cotton bollworm. Control should be timed from the peak of egg hatching to the peak of second-instar larvae, that is, pesticide application before the larvae bore into the fruit. In the early growth stage, 5% flufenoxuron emulsifiable concentrate (Kasike) at 1500--2000 times dilution, 48% chlorpyrifos emulsifiable concentrate (Lesiben) at 1000 times dilution, 50% phoxim emulsifiable concentrate at 1000 times dilution, etc. may be used; in the middle and late stages, indoxacarb and tebufenozide may be used for control. 3) Aphids. Spray control may use 10% imidacloprid wettable powder at 1500 times dilution or 3% acetamiprid emulsifiable concentrate at 2000 times dilution. 4) Damping-off and Rhizoctonia rot. Before sowing, soak the seeds in clean water for 3--4 hours, then soak them in 500 times dilution potassium permanganate solution for 15 minutes, then wash them clean, dry them in the shade, and sow. After emergence, spray 3 times every 7--10 days with potassium permanganate at 800--1000 times dilution (dilute first, then concentrated). When preparing and spraying potassium permanganate, stir continuously so that all the medicinal particles dissolve, and use it immediately after preparation. The concentration used at the seedling stage must not be too high. 5 minutes after spraying the seedlings, spray or rinse the leaves with clean water. Spraying is best done around 9 a.m. or after 4 p.m. 5) Viral disease. This disease is transmitted by aphids. In addition to timely control of aphids, at the early stage of plant disease, 20% moroxydine hydrochloride · copper wettable powder (Virus A) at 500--800 times dilution or 10% mixed fatty acid AS (83--Zengkangji) at 100 times dilution may be used for foliar spray control. Apply once every 5--7 days, for 3--4 consecutive sprays.