Recently, we went to the field of sweet potato production and found that sweet potatoes suffered from the damage of Helicoverpa armigera, leaf curl insects and Spodoptera litura, reminding farmers to pay attention to prevention and treatment.
Hollow worms occur in the south for 2-3 generations a year. Adults bite on tender stems and petioles, and larvae enter sweet potato vines. In addition to harming the seedlings from May to June, 8-10 months are a period of recurrence. At present, some of the sweet potato leaves have been bitten into small holes, the edge of the leaf is bitten into nicks, the protruding part of the leaf veins on the back of the leaf is also eroded, and the exposed tubers are also endangered. The prevention and control methods are mainly sprayed with 90% crystals of trichlorfon 1000-2000 times in adulthood. At the seedling stage, many young stems of sweet potato were killed.
Roller leaf insects occur in the south for 4-5 generations a year. Adults are mostly hidden on the back of the leaves. The larvae have a body length of about 15 mm. They are lively and loving. If touched, the insects quickly fall to the ground. The larvae mainly damage the sweet potato leaves, and often the spine rolls up the corner of the potato leaf to the leaves, and then eats up the leaves, so that the potato leaves are eaten up. The yield and quality of the sweet potato are very harmful. Control methods: When the larvae are harmful to the seedlings, spray them with 40% quick-acting phosphoric acid emulsifiable oil 1500-2000 times, and can receive the efficacy of both the treatment of eggs and worms; or use 50% phoxim emulsion 1000 times, 80-90% The crystal trichlorfon was sprayed with 700-1000 times liquid. When larvae occur more, the larvae in the leaflets can be pinched by hand to prevent proliferation hazards.
Spodoptera litura occurs about five generations a year in the South, and some places will overlap from generation to generation. The adults lay their eggs on the back of the leaves and showed a bread-like shape. The surface of the egg mass turned from yellow to white and dark gray. The larvae were 6 years old and 18-20 mm long. The larvae first eat the lower epidermis of the leaves, leaving the upper epidermis and veins forming membranous patches. The larvae disperse to various places after 2 years of age. Larvae are omnivorous pests. When the densities of insect populations increase, they will not only eat sweet potato leaves, but also eat tender stems and petioles when serious and transfer them to harm. Control methods: Manual removal of dorsal egg masses; before the third instar, the larvae are sprayed and killed by different pesticides according to local conditions. They can be used to propel (1.0% methylcarbamycin, benzoate) to 10 kg water, 15 kg, or 50%. The phoxim emulsion 1000 times, or 90% of the trichlorfon 800-1000 times, or 50% of the killer emulsion 1000 times, was sprayed after 4 pm.
120Ml Urine Cup,Medical 120Ml Medicine Cup,Medicine Cup 120Ml,120Ml Medicine Cup
Luck Medical Consumables Co.,LIMITED , https://www.luckmedical.com