Home › Edible Gardening › Article

What are the control methods for the 28-spotted ladybird beetle (Henosepilachna vigintioctopunctata)?

Edible Gardening 0 views
1. Morphological characteristics: The adult is yellowish-brown and hemispherical. The pronotum usually bears 6 black spots, and each wing cover has 14 nearly round black spots of two sizes, with the black spots not connected at the suture between the two wing covers. The egg is bullet-shaped, yellowish-white when first laid and later brown, with the eggs in an egg mass arranged rather densely. The newly hatched larva is pale yellow, later turning white, spindle-shaped, with many white branched spines on the body segments, and the bases of the branched spines have dark brown rings. The pupa is oval, yellowish-white, with black markings on the back, and the posterior end is wrapped in the cast skin of the last-instar larva. 2. Life habits and

1. Morphological characteristics: The adult is yellowish-brown and hemispherical. The pronotum usually bears 6 black spots, and each wing cover has 14 nearly round black spots of two sizes, with the black spots not connected at the suture between the two wing covers. The egg is bullet-shaped, yellowish-white when first laid and later brown, with the eggs in an egg mass arranged rather densely. The newly hatched larva is pale yellow, later turning white, spindle-shaped, with many white branched spines on the body segments, and the bases of the branched spines have dark brown rings. The pupa is oval, yellowish-white, with black markings on the back, and the posterior end is wrapped in the cast skin of the last-instar larva.

2. Life habits and occurrence patterns

The 28-spotted ladybird beetle occurs throughout Guangxi, with 4 to 5 generations per year in Guangxi, overwintering as adults in weeds at field edges and in soil crevices. It begins activity in March each year, laying eggs and reproducing on spring eggplant or other host plants. Eggs are mostly laid on the underside of leaves, with each female laying an average of about 400 eggs; newly hatched larvae first gather on the underside of leaves to cause damage, and only after the 3rd instar do they gradually disperse. The larvae go through 4 instars in total, and mature larvae hang upside down on the underside of leaves to pupate. The generations of the 28-spotted ladybird beetle overlap, and multiple developmental stages often exist at the same time. During high temperatures and strong light, adults often hide on the underside of leaves; both adults and larvae have light-avoiding and death-feigning habits, and at the slightest vibration they drop down and play dead. In October, after the eggplant harvest, they move to suitable places to overwinter.

3. Control methods

(1) Manual capture and killing: Taking advantage of the adult's death-feigning habit, tap the host plants in the morning and evening, catch the fallen adults in a basin and kill them together. Pick and destroy egg masses during the peak egg-laying period.

(2) Chemical control: Seize the opportunity at larval hatching or the young larval stage to apply pesticides in a timely manner. You can use 20% fenvalerate or 2.5% deltamethrin 3000-fold dilution, or mieshabi 6000-fold dilution, or 50% phoxim emulsifiable concentrate 1000-fold dilution, or 2.5% kung fu emulsifiable concentrate 4000-fold dilution for spraying.

Related Articles