Black Beetles In My Daffodils – Pollen Beetles
Every year my double white daffodils are eaten by little black beetles about the size of a pinhead.
These beetles sound like Pollen Beetles, which can be found from spring until late summer in the flowers of daffodils, sweet peas, runner beans, marrows, roses, dahlias, and Shasta daisies. These beetles normally do not do any harm.
The adult beetles feed on pollen and there is little actual damage to garden flowers, although the beetles can be a nuisance on cut flowers. They can also be of some benefit by transferring pollen between flowers and assisting in the pollination process.
Exceptionally, they may damage unopened flower buds by forcing their way into them to feed. They may also feed on cauliflower heads, causing them to discolour.
Cause:
There are 35 Meligethes species in Britain, most of which develop as larvae in the flower buds of wildflowers. The adult beetles are similar in appearance, being shiny black or greenish-bronze and 2-3mm in length. They have short antennae that end in a small rounded club.
M. aeneus and M. viridescens are two of the most common species and their larvae develop in the flower buds of seed crops of brassicas, turnip, swede, mustard and oil seed rape.
Gardens in arable areas where oil seed rape is grown are likely to be invaded by a large number of pollen beetles when the adults emerge in mid-summer. Pollen beetles overwinter as adults in the soil and leaf litter. Spring flowers, especially yellow ones such as daffodils, will attract the beetles when they re-emerge in the spring.
Control:
Control of Pollen Beetles in gardens is unnecessary because they do little damage and there are good reasons for not spraying.Pesticides will not control beetles concealed within the keel petals of sweet pea and runner bean flowers.Some flowers may be damaged by pesticides, while bees, butterflies and other desirable flower visitors would be endangered by sprays.Pollen beetles migrate into gardens from brassica seed crops, especially oil seed rape, in mid-to-late summer, so spraying would need to be repeated frequently if it were to have any effect.
When cut flowers are brought into a house, Pollen Beetles on the blooms may be a nuisance, as they tend to wander about and head for the brighter light coming from the windows. This can be avoided by placing the vase of cut flowers in a garage or garden shed with a window or open door for a few hours during the day. This will encourage the beetles to vacate the flowers, which can then be taken into the house largely beetle-free. For more information: Click Here
