Meligethes aeneus F Pollen beetle

This generally abundant beetle is associated mainly with members of the Brassicaceae. The

Glischrochilus Hortensis Strawberries
Fig. 207 Adult of Glischrochilus hortensis (xlO).

adults and larvae often cause damage to oilseed rape, white mustard and other brassica seed crops, including cabbage and swede. Adults bite into the buds and this leads to abortion and, potentially, loss of yield. On winter rape, which has considerable powers of compensation and is usually past the vulnerable bud stage before the majority of adults emerge from hibernation, economic damage is rare; spring rape is more vulnerable and also more susceptible, as it flowers later in the season and is less robust. Larvae, which feed in the open blossoms, may also cause abortion of young pods but such damage is of little or no significance. In recent years, large numbers of young adults reared on oilseed rape crops have migrated to, and caused damage to, autumn-grown vegetable crops, especially the developing heads of calabrese and cauliflower; the beetles also invade various ornamental flowering crops in search of pollen, and have often then become a local nuisance.

BIOLOGY

Adults appear in the spring, from late April or early May onwards, and are usually active until June. They often congregate in large numbers on brassicaceous plants, including oilseed rape and weeds such as Sinapis arvensis, where they bite into the buds and opening flowers and feed on the anthers and exposed pollen. Eggs are laid in the flower buds and hatch about 7-10 days later.

Pollen Beetle Meligethes
Fig. 208 Pollen beetle, Meligethes aeneus (x25).

The larvae develop within the opening buds and flowers for 3-4 weeks, passing through just two instars. Fully grown individuals then drop to the ground where they eventually pupate, each in a small earthen cell. New adults emerge in July. They then migrate to open flowers of various kinds of plant, where they feed on pollen. They then seek suitable overwintering quarters in the soil. There is only one generation a year.

DESCRIPTION

Adult 1.5-2.7 mm long, mainly black, with a metallic bronzy-green tinge; elytra finely punctured (Fig. 208). Egg 0.8 x 6.3 mm, elongate with rounded ends, translucent-whitish. Larva up to 4 mm long; body creamish-white, with dark brown to black thoracic and abdominal plates; head black; legs blackish (Fig. 209); anal plate slightly indented posteriorly (cf. Meligethes viridescens, below).

Building Your Own Greenhouse

Building Your Own Greenhouse

You Might Just End Up Spending More Time In Planning Your Greenhouse Than Your Home Don’t Blame Us If Your Wife Gets Mad. Don't Be A Conventional Greenhouse Dreamer! Come Out Of The Mould, Build Your Own And Let Your Greenhouse Give A Better Yield Than Any Other In Town! Discover How You Can Start Your Own Greenhouse With Healthier Plants… Anytime Of The Year!

Get My Free Ebook


Post a comment