Sweet potato stem borer, also known as sweet potato stupid wild borer, sweet potato stupid moth, sweet potato vine head worm, has been distributed in Fujian, Taiwan, Hainan, Guangdong, Guangxi and other regions, causing serious harm to sweet potato planting. Today, we will introduce in detail the pest characteristics, morphological characteristics, living habits and control methods of sweet potato stem borer for your reference.
Harmful features:
Larvae moths into the potato stem as a pest, causing the stem to form a swollen insect thin, affecting nutrient delivery, causing withering, affecting growth and development.
Morphological characteristics:
Adults are 13-16 mm long, males have a wingspan of 30-37 mm, females 30-40 mm, and the head, thorax and abdomen are grayish-white. The lower lip should be extended to the front of the head, longer than the head2. 5-3 times, compound eyes are large and black. The forewings are pale yellow , the base of the wings is brown , with a reticulated stripe in the center , mostly irregular , with two wavy stripes near the outer margin , and the male is often darker than the female. The eggs are oblate oval, light green, and become yellowish-brown 2-3 days after childbirth, with small red spots on the surface. The hatching larvae have a black head, turn yellowish brown after 2 years of age, and appear reddish brown when mature. The body is yellowish brown and slightly purple, and each section after the second section has 12 large and small spots, of which 4 are on the upper and lower sides of the valve and 4 on the back, which are arranged in a trapezoidal arrangement. The pupa is pale yellow to brownish red , with a prominent head , a wing bud reaching the end of the fourth ventral segment , a central longitudinal bulge of the thorax and dorsal , a blunt and rounded abdomen , and 8 spine hooks.
Life Habits:
Guangdong has 4-5 generations of annual growth, with old mature larvae overwintering in winter potatoes or residual potatoes, pupating in early and mid-March of the following spring, and entering the adult stage in mid- and late-March. The first generation is from early April to mid-May, the second generation is from late May to early July, the third generation is from mid-July to mid-August, the fourth generation is from mid-September to late October, and the fifth generation is from early November. Adults are hidden during the day, active at night, phototropism, mating and laying eggs in the evening after feathering, the spawning period is 6-7 days, the eggs are scattered at the branches of the bud, petiole or stem, and the individual grains are arranged in a row, and the egg period is 4-10 days. The hatching larvae burrow in from the petiole, buds, and stems. The larvae that burrow in from the young stems are infested for a period of time and then crawl out and drill into the main stem for harm, the larvae like to moth downwards, and when they are old, they often drill into the stems or rhizomes under the topsoil, and some drill into the potato blocks. The swelling of adult galls in the affected part of the stem, which often excretes insect feces, is one of the important characteristics of identifying this insect. The larvae mature in whitish or yellow thin cocoon pupae at the moth holes at the base of the stem near the soil surface. Predators have macular foot armor (Pheropsophus sp. ), Phnom Penh Green Rifle (Collerdasp. ), Xanthopimpla stemmator Thunberg, etc.
Prevention and control methods:
(1) Clean the countryside in time after harvesting potatoes to reduce the population base of wintering insects.
(2) Rotation.
(3) Potato seedlings are treated with chemicals. 1-2 days before cutting and planting, use 40% Lego Emulsion 1000 times liquid or 90% crystalline Dipheropsis or 800-900 times Dichlorvos Emulsion 800-900 times liquid for seedbed spray or soak the seedlings with Leguo medicinal liquid for 1-2 minutes and then cut cuttings.
(4) Spray the above insecticides 5-7 days after the peak of adult feathering.
(5) 1-2 heads of unstrotilized female moths are packed in a trap, which is effective in trapping adults during the peak period.