Wheat blossom midge can be controlled by broadcasting pesticide-treated soil at the booting stage

The wheat blossom midge overwinters as mature larvae in round cocoons in deep soil and can remain dormant for many years. In spring, when the soil temperature at 10 cm rises to about 7°C, which is when wheat begins jointing, the larvae break out of their cocoons and move toward the soil surface. In mid-April, wheat enters the booting stage, and the larvae successively build earthen cells in the top 3 cm of soil and pupate. The pupal stage generally lasts 8-12 days. In late April, adults emerge, first active on the soil surface, then lay eggs on wheat ears. This coincides with the heading to flowering stage of wheat, and the egg stage lasts 3-7 days. The hatched larvae bore into the glumes of the wheat ear, bite through the seed coat, and feed on the milky sap of the filling grain, causing shriveled grains and empty husks. This is how the blossom midge got its name. Because the insect is very small, its damage is very inconspicuous, and its serious harm is often only discovered at harvest when no grain can be threshed out.

Given that the wheat blossom midge damages grains only at the wheat ear stage, and that before wheat heading the larvae, pupae and adults of the wheat blossom midge all concentrate in or on the soil surface, control can be carried out by broadcasting pesticide-treated soil at the booting stage and by stem and leaf spraying from heading to flowering.

To prepare the pesticide-treated soil, use 5% phoxim granules at 2 kg per mu or 2.5% isofenphos-methyl granules at 1.5 kg plus 20 kg of fine sandy soil, or use 200 mL of 50% phoxim emulsifiable concentrate mixed with 5 kg of water, or 5% chlorpyrifos granules at 600-900 g per mu, prepared with 25-30 kg of wet sandy soil. Broadcast into the wheat field at noon when there is no dew, then shake the wheat plants with a bamboo pole or thin rope so that the pesticide-treated soil falls completely onto the ground surface. Combined with irrigation, the effect is better.

For controlling adults at the heading stage, spray 5% acetamiprid wettable powder at 2000 times dilution, 80% dichlorvos emulsifiable concentrate at 1000 times dilution, or 10% imidacloprid wettable powder at 1500-2000 times dilution, as well as various pyrethroid insecticides such as 4.5% beta-cypermethrin at 1500 times dilution, or organophosphate-pyrethroid mixtures such as 25% kuishaling emulsifiable concentrate at 1500 times dilution. Be sure to observe the development progress of wheat in the specific field, apply 2-3 times from the wheat "cracking" stage to before flowering, pay attention to mixing enough water, spray evenly and thoroughly, and choose dusk or after the temperature drops in the afternoon for spraying whenever possible.

In areas where wheat blossom midge overwintering has been identified, it is recommended to adopt the control measure of broadcasting pesticide-treated soil at the heading stage, and to continue this for several years and adhere to unified control. In fields where pesticide-treated soil has not been broadcast, closely monitor the timing of adult emergence and egg laying, and spray to control adults according to how much this overlaps with the heading and flowering stage of wheat, or adopt the control concept of protecting the ear, starting adult control as soon as the ear stage begins, just as some areas control wheat scab, and the corresponding pesticides can also be mixed.