Beet root weevil

Adult

• The beetles are black, but their body is covered with many small scales that give the insect a velvety grey colour.
• The wings are normally developed and the beetles fly well. The antennae are elbowed, the legs are walking legs, and the tarsi have 4 segments.
• The pale abdomen has characteristic black dots and round spots. They give the species its name punctiventris, which means 'with dots on the abdomen'.

Egg

Females lay their eggs in the soil, mainly in beet rows, to a depth of up to 1 cm. One female lays 100–300 eggs.

Damage

• The beetles eat away the cotyledon 'fork', bite through the small stem and chew out pieces, leaving notches on the leaves.
• The larvae feed on the fine rootlets of seedlings, then damage the central root, going down into the soil to a depth of up to 30 cm.

When to look

They do the most damage to beet at the cotyledon 'fork' stage and when the first pair of true leaves appears.

How to count

Beetle emergence from winter diapause and their migration onto crops should be monitored systematically.

No rate and no spray timing here: both come from the label and the register.

Biological control

Crops are sprayed with insecticides of biological origin. They are slightly less effective than chemical ones, but when applied preventively they can protect seedlings from damage.

Yield loss

In its lifetime one beetle eats 13 g of green matter, which is 100 times its own weight, so the crop stand becomes thinned.

Harvest quality

Because of larval damage to the roots, the weight and sugar content of the storage root decrease.

Overwintering

Beetles were recorded waking on last year's beet fields from early April to May, when they gradually move into the upper soil layers.

Migration

• Just after coming out of the soil, the beetles move on foot, covering about 200 m in 24 hours. On sunny, hot days, when the air warms to +20…+25 °C and above, they start to fly and cover about 10 km a day.
• Beetles mainly colonise the edge strips of crops on the side facing their overwintering sites.

Favourable conditions

In spring, the beetles wake up when the mean daily air temperature is +6…+7 °C and the soil surface warms to +15 °C.

Where it is found

• A widespread pest of sugar beet seedlings in most beet-growing regions.
• The range covers Vinnytsia, Volyn, Kyiv, Kirovohrad, Poltava, Sumy, Cherkasy and Chernihiv oblasts.

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. 129, 130
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. 98, 99
4. Photos: carnifex, iNaturalist, CC BY 4.0 · Schmidt Péter, GBIF, CC BY 4.0 · Tóth Norbert, GBIF, CC BY 4.0