Which common crops are sensitive to pesticide formulations?
1. Dichlorvos: Stone fruits and kiwifruit are very sensitive, so it is prohibited. Sorghum and Chinese rose are sensitive to dichlorvos emulsifiable concentrate and should not be used. Corn, beans, cucurbit seedlings and willow are also relatively sensitive, and dilution must not be lower than 800 times. Dichlorvos causes obvious phytotoxicity to ornamental plants such as wintersweet, cherry, peach, apricot, Amygdalus triloba, Twentieth Century pear and Jingbai pear, and under normal circumstances other types of insecticides should be used instead. Dichlorvos also causes varying degrees of phytotoxicity to rhododendron, Salix matsudana, kiwifruit, Sophora japonica, walnut and cucurbits.
2. Trichlorfon: Stone fruits and kiwifruit are very sensitive, so it is prohibited. Sorghum and beans are especially sensitive and should not be used. Cucurbit seedlings, corn and apple (varieties such as Shuguang and Marshal) are also prone to phytotoxicity from trichlorfon in the early stage. It has phytotoxic effects on cherry blossom, wintersweet and the Golden Delicious apple variety.
3. Phoxim: Sorghum is sensitive and should not be sprayed; for corn, only granules can be used to control the Asian corn borer. Cucumber and kidney bean are sensitive to this pesticide; spraying with 50% emulsifiable concentrate at 500 times may cause phytotoxicity, and even at 1000 times there may be slight phytotoxicity. Sugar beet is also relatively sensitive to phoxim, so when treating seed by mixing and covering, the dose and covering time should be appropriately reduced. At high temperatures it is sensitive to leafy vegetables and easily burns leaves. The mechanism by which organophosphorus pesticides such as phoxim cause discoloration and other phytotoxicity is that strongly hydrophobic organophosphorus pesticides are adsorbed by chloroplasts or surrounding tissues, causing chloroplast function to become disordered, thereby blocking electron transfer reactions, namely the Hill reaction, inhibiting photosynthesis and causing discoloration; the more severe the phytotoxicity, the lower the carbohydrate content in the plant body and the relatively greater the total nitrogen content. ① The pesticide solution should be used immediately after preparation and must not be mixed with alkaline pesticides. ② This pesticide decomposes easily in light, so field spraying is best done in the evening.
4. Dimethoate and omethoate: Kiwifruit and ginseng fruit are especially sensitive to dimethoate and omethoate, so it is prohibited. Hops, Asteraceae plants, some sorghum varieties, tobacco, jujube, peach, pear, citrus, apricot, plum, olive, fig and other crops are sensitive to 40% dimethoate or omethoate emulsifiable concentrate diluted below 1500 times. If peanuts are treated too many times, the cotyledons will not close at night, so attention should be paid to the concentration before use. It can cause obvious phytotoxicity to Rosaceae ornamental plants such as wintersweet, cherry blossom, flowering peach, Amygdalus triloba, Chaenomeles speciosa, apricot and pear, and it is also very harmful to Acanthaceae plants such as shrimp plant and coral flower.
5. Lime sulfur mixture: Peach, plum, Japanese apricot, pear, grape, beans, potato, tomato, onion, ginger, melon, cucumber, etc. It easily causes phytotoxicity to the young and tender tissues of fruit trees such as grape, peach, pear, plum, Japanese apricot and apricot, so it should be used with caution, preferably sprayed in the leaf-fall season, and must not be used in the growing season or during the flowering and fruiting period. It has certain phytotoxicity to kiwifruit, grape, cucumber and leguminous flowers.
6. Bordeaux mixture: Potato, tomato, pepper, cucurbits, peach, plum, pear, apple, persimmon, Chinese cabbage, soybean, wheat, lettuce, etc. Peach, apricot, plum and hawthorn are especially sensitive to copper ions and are relatively sensitive during the production season, so they should be used with caution. When the lime in Bordeaux mixture is lower than the double-strength formula, it easily causes phytotoxicity to apple and persimmon, so the double-lime formula should be used; when lime is higher than double strength, grape is prone to phytotoxicity, so the half-lime formula should be used. For other tree species, different formulas and ratios should also be selected according to their characteristics. For example, for apple, which is sensitive to copper but tolerant to lime, a double or multiple lime formula can be used; for pear, which is not very sensitive to either lime or copper, an equal-lime formula can be used; for grape, which is sensitive to lime but tolerant to copper, a half-lime formula can be used. Mixing with organophosphorus pesticides should be done with caution and used immediately after mixing. Bordeaux mixture can be sprayed only 10 days after spraying lime sulfur mixture, and lime sulfur mixture can be sprayed only 20—30 days after spraying Bordeaux mixture. ① Avoid application on damp cloudy days or before fog has dried, to prevent phytotoxicity. Because copper sulfate has strong permeability, what is washed off by rain or dew is lime, and what remains is copper ions, and copper ions are highly corrosive and easily damage leaves and young fruit. In summer, avoid the midday sun when spraying, so as to prevent high temperatures from causing phytotoxicity caused by lime. When spraying in the rainy season, increase the lime dosage as appropriate when preparing the mixture. ② It must not be mixed with alkaline agents; mixing Bordeaux mixture with lime sulfur mixture, thiram, thiram, asomate, etc., or alternating them with too short an interval, easily causes phytotoxicity. ③ Bordeaux mixture should not be prepared in metal containers. ④ Bordeaux mixture is toxic to silkworms, so it must never be used on mulberry trees. ⑤ Use immediately after preparation. Bordeaux mixture preparation: First, pour the dilute copper sulfate solution into the concentrated lime milk while stirring; second, pour the diluted lime milk and copper sulfate solution simultaneously into a stirred bucket full of water while stirring. This preparation method is both simple and convenient, and the prepared Bordeaux mixture settles slowly and has a good protective effect after use.
7. Acephate: Not suitable for use on mulberry or tea trees.
8. Triazophos: Sugarcane.
9. Chlorpyrifos: Tobacco.
10. Isocarbophos: When used on citrus during high-temperature drought seasons above 28-30 degrees, striped mottling appears on the fruit.
11. Fenthion: Seedlings of cruciferous vegetables, pear, peach, cherry, sorghum and hops are sensitive to this pesticide and prone to phytotoxicity, so it should not be used.
12. Fenitrothion: Sorghum, corn and crucifers such as Chinese cabbage, rapeseed, radish, cauliflower, cabbage, green leafy cabbage and savoy cabbage are sensitive to this pesticide, so pay attention when using it.
13. Malathion: Tomato seedlings, cucurbits, cowpea, sorghum, cherry, pear and some apple varieties are sensitive to this pesticide, so pay attention to the concentration when using it.
14. Pyridaphenthion: It must not be used at the same time as 2,4—D herbicide; if the interval between the two is too short, phytotoxicity is likely to occur.
15. Cartap: Rice flowering stage, and seedlings of cruciferous vegetables such as Chinese cabbage and cabbage.
16. Bisultap: Seedlings of cruciferous vegetables such as Chinese cabbage and cabbage, and cotton foliar spraying. Beans and citrus fruit trees are sensitive to it, so only low concentrations can be used.
17. Monosultap: Cotton, tobacco, kidney bean, potato and certain beans.
18. Fenobucarb: Cucurbits, beans and Solanaceae crops.
19. Isoprocarb: Tuber crops.
20. Carbaryl: Cucurbits.
21. Carbofuran: It can only be applied by burying in the root zone and must not be dissolved in water for spraying.
22. Buprofezin: Chinese cabbage and radish.
23. Imidacloprid: Beans and cucurbits.
24. Petroleum emulsion: It easily causes phytotoxicity to certain peach varieties, so it is best used in the leaf-fall season. Dithane (99.1% mineral oil emulsifiable concentrate) can be mixed with most insecticides and fungicides; it can reduce evaporation of the pesticide solution, improve pesticide adhesion and protect insecticide varieties susceptible to ultraviolet light, and therefore has a certain synergistic effect. It can be mixed with agents such as abamectin, Bt, imidacloprid, diflubenzuron, methomyl, copper hydroxide and copper succinate-glutarate. However, this product must not be mixed with sulfur-containing pesticides, Bordeaux mixture, dimethoate, propargite, carbaryl, chinomethionat, folpet, chlorothalonil or azoxystrobin pesticides. At the same time, note that after spraying the above pesticides on fruit trees, Dithane must not be sprayed again within 14 days, otherwise phytotoxicity will occur. Method of use: first add a certain amount of water to the container, then add the specified amount of Dithane to the water, then add enough water. If mixing with other pesticides, first mix the other pesticides with water evenly, then pour in Dithane; the order must not be reversed. To prevent separation of the pesticide and water, stir continuously. When using machine oil emulsion in summer, some tree species may suffer phytotoxicity, so a test should be done first.
25. Rosin mixture: Using rosin mixture in summer causes obvious phytotoxicity to persimmon, and in spring and summer it has adverse effects on citrus.
26. Rosin-soda mixture: Deciduous fruit trees are all quite sensitive to it, so it should not be used during the summer growing season.
27. Mancozeb: Tobacco, Cucurbitaceae and certain pears. Applying mancozeb when pear fruits are small easily causes spots on the fruit surface. High concentrations cause blighted spots on the edges of rice leaves.
28. Thiophanate: When controlling diseases and pests of kiwifruit, avoid using thiophanate-methyl. It can be mixed with many pesticides, including alkaline agents, but should not be mixed with copper formulations.
29. Carbendazim: It can be mixed with general fungicides, but should be used immediately after preparation. It must not be mixed with copper formulations.
30. Chlorothalonil: It easily causes phytotoxicity to pear and persimmon, so it should not be used. It also must not be used within 20 days after apple petals fall. High concentrations easily cause phytotoxicity to pear, persimmon, peach and Japanese apricot.
31. Sulfur: Cucumber, soybean, potato, plum and pear.
32. Flusilazole: Certain pear varieties are very sensitive during the young fruit stage (before May), so it is forbidden.
33. Cuprous oxide: Fruit tree stage and young fruit stage.
34. Propargite: Prohibited on pear trees. For cucurbit, bean and cotton seedlings below 25 cm, dilution must not be lower than 3000 times. Propargite causes phytotoxicity to the young leaves of citrus spring shoots, producing brown imprinted spots; on fruit, if the concentration used is too high or the dosage too large, yellow striped or irregular ring patterns will appear on the fruit surface, affecting fruit appearance, and application at high temperatures easily affects the fruit.