Melon aphid, cotton aphid, belonging to Homoptera, Aphidae, commonly known as honey stinkbug and oil stinkbug, is a worldwide pest, which is seriously harmful in dry years. It mainly harms cucurbitaceae, beans, eggplant, spinach, onion, onion and other vegetables.
1. Hazard characteristics. Adults and nymphs suck juice on the back of leaves and tender stems. After the young leaves and growing points of melon seedlings were killed, the leaves shrank, the seedlings grew slowly and wilted, and even the plants died ahead of schedule, and the old leaves suffered, shortening the fruiting period and reducing the yield. In addition, it can spread viral diseases.
2. Morphological recognition. Godmother is1.7mm long and 1. 1 mm wide, wingless, with compound eyes in dark green and reddish brown. Wingless viviparous female aphid: body length 15- 1: 9mm, yellow-green in summer, dark green in spring and autumn, long cylindrical abdominal tube with ripples. The tail is black with 4-7 bristles.
Winged viviparous female aphid: body length 1.2— 1.9mm, yellow or light green. The chest backboard is black, and there are 3-4 pairs of black spots on both sides of the back. The ventral tube and tail are the same as those of wingless viviparous female aphids.
Aphids: wingless aphids, with a body length of 1.63mm, yellow or yellowish green in summer, blue-gray in spring and autumn, and red compound eyes. If there are winged aphids, they are grayish yellow in autumn and black in the second half. Others are the same as wingless aphids.
3. Living habits. 20-30 generations per year. Eggs overwinter in the branches and leaves of Prunella vulgaris, such as hibiscus flowers, pomegranate flowers and rhamnose, and adult aphids and nymphs can also overwinter in the greenhouse without diapause. In mid-March, when the 5-day average temperature was stable above 6℃, the overwintering eggs began to hatch, and at the end of April, winged aphids were produced and flew to the open space to do harm. In late autumn and early winter, winged aphids will move into the reserve, and prolific aphids will mate and lay eggs for the winter. The optimum breeding temperature is 16-22℃, and the arid climate is suitable for the occurrence of melon aphids. Generally, plants that grow too tender have more topdressing, high nitrogen content and many aphids. In open field planting, Gua Tian, which is generally close to the overwintering site and host plants of melon aphids and the protected areas, is seriously damaged, and the nesting wind is also strong. Intercropping with rape field, yellow rape petals can attract aphids in April-May, or melon nursery is close to rape field, so melon aphids migrate early and the aphids are seriously harmful.
4. Prevention and control methods
Agricultural control: Selecting insect-resistant varieties with hairy leaves, sowing them early and eradicating weeds in fields and ditches and ponds in time can eliminate some aphid sources. Deal with withered old leaves and harvested residual plants in time to clean the countryside.
Physical control: use silver film to avoid aphids, covering or hanging strips. It can also play a role in preventing viral diseases.
Biological control: protect natural enemies, such as spiders, ladybugs, lacewings, syrphids, aphid bees, etc.
Smoking: Cucumbers planted in protected areas can be smoked with chemicals. For example, 400-500 grams of insecticide for killing aphids are used each time, dispersed into 4-5 piles, lit with dark fire, smoked and sealed for 3 hours. It can also be fumigated with 22% dichlorvos or 10% insecticide for killing melon aphids, with 300-500 grams of insecticide per mu or 400 grams of 80% dichlorvos EC mixed with appropriate amount of sawdust.