As summer approaches and temperatures rise, various pests become more active. For greenhouse cucumbers, it's important to be vigilant against thrips, as improper control can seriously affect cucumber yield and quality. So, what pesticides are effective in controlling thrips on greenhouse cucumbers? Let's find out.
What Pesticides are Effective in Controlling Thrips on Greenhouse Cucumbers?
Harmful Symptoms of Thrips on Greenhouse Cucumbers:
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Western Flower Thrips: Feeds on the stems, leaves, flowers, and fruits of cucumbers, causing petals to fade, leaf curling, and scars on stems and fruits, ultimately leading to plant withering.
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Onion Thrips: Both adult and nymph feed on the juice of cucumber flowers, ovaries, and young fruits, leaving behind grayish-white point-like feeding marks. Severely affected petals curl, causing premature withering of flowers and affecting fruit setting and yield.
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Palm Thrips: Adult and nymphs feed on the sap of cucumber tender shoots, leaves, flowers, and young fruits. Leaves of affected cucumbers turn black-brown, and severe cases result in slow plant growth, shortened internodes, and even fruit drop, significantly affecting yield and quality.
Effective Pesticides for Controlling Thrips on Greenhouse Cucumbers:
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Spraying Method: Generally, pesticides effective against piercing-sucking pests can be used to control thrips. Options include 25% imidacloprid wettable powder at a concentration of 2000 times, or 5% diafenthiuron wettable powder at a concentration of 2500 times, or 2.5% chlorfenapyr suspension concentrate at a concentration of 1000-1500 times, or 25% acetamiprid water dispersible granules at a concentration of 5000-6000 times, or 80% dichlorvos emulsifiable concentrate at a concentration of 400 times. Spray evenly, apply every 5-7 days, and alternate between different pesticides 2-3 times.
Pesticide Application Considerations:
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Killing Eggs and Pupae: The main targets of pesticide spraying are thrips nymphs and adults, with no effect on eggs and pupae. Untreated eggs will hatch into nymphs, and pupae will emerge as adults. Therefore, pesticide products that also kill eggs and pupae should be chosen, such as pyriproxyfen.
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Adjusting Application Time: Thrips are nocturnal and generally feed at night. Therefore, adjust the spraying time to dusk to kill thrips while they are feeding, for the best effect.
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Increasing Solution Viscosity: Thrips are good jumpers and flyers. Adding 50 grams of granulated sugar to the pesticide solution can attract them and increase the viscosity of the solution, preventing thrips from jumping, resulting in better control.
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Alternate Pesticide Use: Thrips have certain resistance to multiple pesticides, and the effect of commonly used insecticides may not be ideal. It is recommended to use a combination of different pesticides for control.
In conclusion, thrips infestation on greenhouse cucumbers is quite common and can cause issues such as flower and fruit drop, flower withering, and deformed fruits, significantly affecting yield and quality. Therefore, prevention and control measures should not be neglected. However, pesticide application is only a last resort, and strengthening management and preventive measures should be the focus of attention.
