Legume Pests: Acacia Moth

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

Acacia moth, also called bean moth, is especially harmful in the south of the forest-steppe and in the steppe. This is one of the most dangerous pests. Her tastes include lentils, peas, lupines, soybeans, beans and acacia (both white and yellow). Sometimes she manages to get to the pulp and seeds of watermelons. Caterpillars that attack beans and eat out tender seeds are the main cause of damage. Often they, along with the affected beans, end up in storage facilities, where they finish developing. The seeds attacked by pests lose their germination and market value. Acacia moth usually produces two or three generations per year, which in turn has an extremely negative effect on the volume of the crop and its quality

Meet the pest

Acacia moth is a harmful butterfly with wingspan ranging from 22 to 30 mm. Its front yellowish-grayish wings are equipped with transverse white stripes, and the translucent hind wings are light gray in color and are framed with dark stripes along the edges.

Eggs of the acacia moth are oval in shape, reach a size of about 0.7 mm and are endowed with reticular membranes. Initially, they are colored milky white, and after a while, tiny reddish specks appear on them. Pale green caterpillars grow in length from fifteen to twenty two millimeters. And the size of the shiny brownish pupae ranges from seven to ten millimeters.

Caterpillars that have completed their development hibernate in the soil, comfortably nestling in silky and rather dense cocoons. Pest pupation usually occurs in mid-May, and the emergence of butterflies can be observed already at the end of May or at the very beginning of June. Winged pests fly mainly in the evenings and at night, while additionally feeding on flowers of a wide variety of cultures.

Some time later, the females lay eggs one at a time on unripe beans or on staminate tubes, dried corollas, or on the remains of cups. Their total fertility varies from two hundred to three hundred eggs. Embryonic development usually takes from 4 to 21 days - a more accurate figure directly depends on the temperature. The reborn caterpillars immediately begin to feed on grain, eating the grains outside with a special appetite (as for the caterpillars of younger ages, their nutrition occurs mainly under the skin of the grains). Acacia moth caterpillars can easily move from one bean to another. In general, their development requires from twenty to forty days, during which the gluttonous parasites pass five ages. And after the end of feeding, they descend to the soil surface and, having made their way into the soil, pupate there in grayish-whitish cocoons. The development of both the pronymph and the pupae takes approximately the same amount of time - from twelve to seventeen days.

How to fight

It is recommended that pea crops be removed from yellow and white acacia whenever possible, and deep autumn plowing can largely prevent the emergence of butterflies. And, of course, it is imperative to deal with weeds.

Before the revival of voracious caterpillars begins, areas are sprayed with insecticides. By the way, these treatments are often combined with treatments against pea weevils. Especially effective against acacia moth will be "Phosphamide" and "Chlorophos". Treatments with biological pesticides also serve well.

Reduces the number of acacia moths and a number of natural factors: it can be both wintering conditions and all kinds of fungal diseases (especially white muscardine). The eggs of these pests are infected with trichograms, and the caterpillars are infected with braconids and over seventy species of predatory entomophages.