Destructive pea louse

Damage

• It sucks sap from plants and injects toxic enzymes into them. Aphid feeding suppresses plant growth.
• It is most dangerous when the aphid colonises the stem tips at the start of flowering: stem growth is delayed and the fruit does not develop fully.

When to look

• In spring and summer, grain legume crops are inspected periodically to detect the pea aphid in time.
• Colonisation of pea crops begins during stem elongation, and aphid activity increases at the budding stage.
• They colonised soybean crops from emergence to the budding stage.
• Mass development of aphids on soybean was recorded from pod formation to pod ripening.

How to count

Aphids in pea crops are counted with a sweep net, counting the number caught per 100 sweeps.

Agronomy

• Sow grain legumes early and within a short period, and grow early-maturing varieties.
• Cut perennial grasses low to destroy the aphid eggs.

Yield loss

• Aphid feeding reduces straw weight, the number of pods and grain weight.
• If the aphid multiplies heavily, the pea crop can be lost completely.

Overwintering

Eggs overwinter on the stem bases of perennial grasses.

Migration

In the third generation, some of the nymphs become winged females. They fly over to annual legume plants and form new colonies there.

Favourable conditions

• An early spring, an average daily air temperature of +18..+22°C in the spring and summer period, 10–15 mm of rainfall per ten-day period without downpours, and breaches of crop cultivation practices threaten mass reproduction and high harmfulness.
• In dry, warm weather with moderate humidity, an increase in aphid numbers and harmfulness should be expected.

Natural enemies

Mass development and spread of the aphid are held back by natural enemies (predators and parasites) and by insect diseases caused by entomophthoran fungi.

Every fact rests on a quote from its source, and each quote was checked against the page it is printed on.

1. Зайцева І. А., «Сільськогосподарська ентомологія. Курс лекцій», навчальний посібник, 237 с. · Дніпровський державний аграрно-економічний університет, Дніпро, 2021 · p. 118, 119
2. EPPO Global Database · European and Mediterranean Plant Protection Organization
3. Прогноз фітосанітарного стану агроценозів України та рекомендації щодо захисту рослин у 2025 році · Держпродспоживслужба, НААН, НАН · p. 73, 74, 80, 81
4. Photos: Mihajlo Tomić, iNaturalist, CC BY 4.0 · Frank Peairs, Colorado State University, Wikimedia Commons, CC BY 3.0 · Clemson University - USDA Cooperative Extension Slide Series,, Wikimedia Commons, CC BY 3.0