Beet Root Aphid (Pemphigus Fuscicornis)

Pest Type: Sugar Beet Pest

Row: Equine – Homoptera

Family: Pemphigi – Pemphigidae

It is found everywhere. Damages beets, quinoa, and other quinoa. A wingless parthenogenic female 2.1-2.6 mm in size has an ovoid body, yellow-brown or greenish in color; the upper part of the head, antennae, legs, plates of the spiracles are brownish and covered with a wax coating, on the end of the body is a bundle of long (1-1.5 mm) wax-like threads; antennae short, in older forms 5 segments, in wintering – 6 segments. The larva of the first age (“vagrant”) – slender, ellipse-like, greenish or yellow-gray; the larvae that feed are covered with a waxy coating; antennae with 4 segments. A winged female 2.5 mm long, rounded; the head, antennae, chest, and legs are black-brown, the abdomen is light yellow, the eyes are facet. Females and males of the amphigone generation are wingless and without proboscis.

Wingless, mature, parthenogenetic females of a special wintering from overwintering in the soil at a depth of 16-60 cm, in areas littered with blotch weeds. It is believed that the appearance of wintering parthenogenetic females is due to the restructuring of the development cycle associated with the loss of forms that develop on the primary host – American poplar, which is not in Europe. In spring, at a soil temperature at a pest depth of 10-12 ° C, females overwintered without restoring nutrition, 20-30 larvae are regenerated. For the full development of embryos, the required sum of positive temperatures at a depth of 30 cm, which is 460-490 ° C. In the forest-steppe of Russia, the revival of larvae occurs more often in the second half of May.

Larvae of the first age (“strollers”) are very mobile. Some of them remain on the roots of haze weeds in wintering places, the rest goes to the surface of the soil, quickly moving in search of fodder plants. They can be transported by wind, water, and tillage tools, which help to populate new crops of sugar beets. Especially dangerous foci that formed on the blotch weeds, if they were clogged with a culture-predecessor of sugar beets (usually wheat). “Strollers” penetrate the soil to the roots of beets and after 10-12 days of feeding turn into live-bearing summer females. The fertility of summer females is 20-80 larvae. Between May and October, 8-10 generations develop.

A rapid increase in aphid abundance is observed in July-August. The formation of new foci occurs due to the intensive resettlement of tramps. In late August and early September, part of the larvae turns into nymphs, then into winged females, which fly to poplars, where males and amphigone females revive. Sexual individuals do not feed. After fertilization, the females lay a small number of eggs in the cracks of the cortex. The bulk of the fertilized eggs during the winter die, die in the spring and regenerate larvae. Wintering females appear at the same time as them. Summer individuals occur before the onset of low autumn temperatures (5-7 ° C).

Favorable conditions for the mass reproduction of beetroot aphids consist of years with little rainfall and high temperature during the growing season. Aphids feed on panicled indigenous ones, which leads to withering and death of the whole plant. Heavily damaged root crops are easily harvested from the soil. In some years, beet harvest is reduced to 30%, sugar content – up to 2-4%. Uterine beets are more affected by the pest.

The root aphid populates mainly the edges of the field, after which the number of cells grows rapidly, covering a significant part of the plantation. The number of root aphids is limited by predatory insects: coccinellids, goldfish, earwigs, ground beetles, carnivorous bugs, etc. In wet weather, aphid mass death is observed due to infection with the fungus Entomophtora thaxteriana Petch.

Protective measures.Weed control. Complete thorough harvesting of root crops. Placement of sugar beets in crop rotation after winter wheat was sown on steam. Respect for spatial isolation from last year’s plantings. Proper storage of manure, preventing it from overgrowing with blotch weeds. Stubble husks and deep autumn plowing after harvesting crops and other predecessors of sugar beets. Before laying in the karats, it is necessary to sort out the uterine root crops, removing damaged ones. Based on the digging and inspection of root crops in 10 field sites in July-August, one should adhere to the following gradation of the economic threshold of harmfulness: a low degree of plant population by larvae and aphid adults – 1%, medium – 2-10%, high – more than 10%. In the case of dangerous numbers, it is necessary to first treat the edges of the field and the pests with insecticides.

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