The commercial natural enemies on the Chinese market mainly include Trichogramma wasps, predatory mites, etc.
Trichogramma is the parasitic natural enemy product with the largest artificial reproduction volume and the widest application range in my country. The use of tussah cocoons to mass-produce pine caterpillar Trichogramma wasps and artificial release in the field to control corn borers have been used for nearly 20 years in some areas of Northeast my country and North China. This technology is highly mature and effective. During the bee release period, when the emergence rate of the overwintering larvae of the corn borer reaches 20%, push back 10 to 11 days, which is the first egg stage of the field corn borer. This is the first suitable bee release period for Trichogramma, and then Pushing back another 5 days is the initial peak period of borer eggs. The second bee release can control the first generation of borer eggs in the corn field. The number of bee releases: The number of Trichogramma releases in the field should be based on the number of corn borer eggs in the field. Determined by the egg-laying pattern, the development period of Trichogramma and the life span of Trichogramma in the field, it is more appropriate to release bees 2 to 3 times; the amount of bees released per hectare is 15 10,000 to 225,000 bees; the appropriate method for releasing bees is to set up 15 release points per hectare, and directly attach bee cards to the back of corn leaves.
Predatory mites like to eat the eggs of harmful mites, and the amount of prey they eat is large. One predatory mite can eat 6 spider mites or 80 rust ticks in a day, and can eat 300 to 500 spider mites or 2,000 spider mites in a lifetime. ~3000 rust ticks, long control time, usually released in August, can be controlled until before fruit picking. The predatory mites can actively search for harmful mites; the prey targets are red ticks on various fruit trees, flowers, greenhouse vegetables, edible fungi, and garden plants. Spiders, rust ticks, tarsal line mites, thrips and other small mite pests; during the release period, July to August are high temperatures and droughts, which is the outbreak period for citrus spider mites and rust ticks, and most orchards at this time also have relatively high levels of pests and diseases. single, so this is the best time to release predatory mites; the release time is generally cloudy or in the evening, and it is best not to encounter rain within 1 to 2 days after release; the release ratio is generally for 3-year-old fruit trees, each tree is about There are 10,000 leaves. When there are 2 red spider mites on each leaf, and there are 20,000 red spider mites in a tree, releasing 100 predatory mites at this time can control the red spider mites within 30 days, that is, the difference between predator mites and red spider mites. The release ratio is 1:200.