Symptom Identification and Control Methods for Soybean Hawk Moth
Symptoms and Control of Soybean Hawk Moth
(Agricultural Wealth Network) Soybean hawk moth, also known as soybean sphinx moth, mainly damages leguminous vegetables such as edamame and cowpea.
Damage Symptoms The soybean hawk moth feeds on leaves as larvae. Young larvae eat leaves into a net-like or notched pattern, and after the third instar the larvae can eat all the soybean leaves, preventing the plants from setting pods, which greatly affects yield.
Occurrence Pattern Mid-to-late July to early August is the peak period for adult egg-laying, late July to late August is the peak period for larval damage, and in early September the light yellow mature larvae enter the soil to overwinter.
Life Habits Adults: Adults hide by day and come out at night, and have a strong tendency toward black light traps. They begin activity in the evening and have strong flying and migration abilities. They mate at night, and lay eggs 3 days after mating. Eggs are mostly scattered on the underside of soybean leaves, generally 1 to 2 eggs per leaf, and hatch into larvae after an egg period of about 7 days. Larvae: Larvae are photophobic, mostly staying on the underside of leaves or on branches and stems during the day, and feeding strongly at night; on cloudy days they can feed all day. First and second instar larvae eat little and generally do not move between plants to cause damage. After the fourth instar they have the habit of moving to other plants to cause damage. Fifth instar larvae show a sharp increase in food consumption, accounting for more than 90% of the total food intake. The larval period is 30 to 35 days.
Occurrence Conditions Drought is not conducive to the occurrence of the soybean hawk moth. It occurs more heavily in densely growing plants, low-lying areas, and fertile silt soil; early-maturing soybean varieties suffer more serious damage. During pupation and emergence, if rainfall is moderate, the occurrence is more severe. If there is too much rain, the occurrence period is delayed.
Control Methods Trapping and killing adults: Taking advantage of the adults' strong phototaxis, set up black light traps to kill adults, which can reduce the number of eggs laid in soybean fields and lessen the damage. Chemical control: The appropriate period for controlling soybean hawk moth larvae should be before the third instar. Use 4.5% beta-cypermethrin at 1500 to 2000 times dilution per mu, or 50% phoxim emulsifiable concentrate at 1500 times dilution for spraying, with 50 kg of spray liquid per mu. Because the larvae are accustomed to hiding by day and coming out at night, spraying should be done after 5 p.m.
Damage Symptoms The soybean hawk moth feeds on leaves as larvae. Young larvae eat leaves into a net-like or notched pattern, and after the third instar the larvae can eat all the soybean leaves, preventing the plants from setting pods, which greatly affects yield.
Occurrence Pattern Mid-to-late July to early August is the peak period for adult egg-laying, late July to late August is the peak period for larval damage, and in early September the light yellow mature larvae enter the soil to overwinter.
Life Habits Adults: Adults hide by day and come out at night, and have a strong tendency toward black light traps. They begin activity in the evening and have strong flying and migration abilities. They mate at night, and lay eggs 3 days after mating. Eggs are mostly scattered on the underside of soybean leaves, generally 1 to 2 eggs per leaf, and hatch into larvae after an egg period of about 7 days. Larvae: Larvae are photophobic, mostly staying on the underside of leaves or on branches and stems during the day, and feeding strongly at night; on cloudy days they can feed all day. First and second instar larvae eat little and generally do not move between plants to cause damage. After the fourth instar they have the habit of moving to other plants to cause damage. Fifth instar larvae show a sharp increase in food consumption, accounting for more than 90% of the total food intake. The larval period is 30 to 35 days.
Occurrence Conditions Drought is not conducive to the occurrence of the soybean hawk moth. It occurs more heavily in densely growing plants, low-lying areas, and fertile silt soil; early-maturing soybean varieties suffer more serious damage. During pupation and emergence, if rainfall is moderate, the occurrence is more severe. If there is too much rain, the occurrence period is delayed.
Control Methods Trapping and killing adults: Taking advantage of the adults' strong phototaxis, set up black light traps to kill adults, which can reduce the number of eggs laid in soybean fields and lessen the damage. Chemical control: The appropriate period for controlling soybean hawk moth larvae should be before the third instar. Use 4.5% beta-cypermethrin at 1500 to 2000 times dilution per mu, or 50% phoxim emulsifiable concentrate at 1500 times dilution for spraying, with 50 kg of spray liquid per mu. Because the larvae are accustomed to hiding by day and coming out at night, spraying should be done after 5 p.m.