Pollen beetle forecast

Background

Adult pollen beetles (Brassicogethes spp.) are occasional pests of cauliflower and broccoli. The adult beetles feed on the curds or florets causing physical damage. This type of damage usually occurs in mid-summer when new adults emerge from oil seed rape crops and move into other areas to feed. They are also often found in flowers at this time. These new adults feed for a period of time and then seek hibernation sites, for example in leaf litter at the base of hedges. They overwinter as adults and emerge from hibernation in spring, when they can again be seen feeding on flowers such as dandelions. They then move to suitable host plants such as oil seed rape to lay eggs. Once hatched, the larvae feed on flower buds and then drop to the soil to pupate, from which the new generation of adults emerges.

The pollen beetle migration from oil seed rape to other host crops is likely to start in the third week of June at the warmest sites.

Location	Estimated start of pollen beetle migration into edible brassica crops
Cornwall - Hayle	22 Jun
Kent - Sandwich	24 Jun
Suffolk - Ipswich	24 Jun
Warwick, Wellesbourne	20 Jun
Norfolk, Norwich	26 Jun
Lincolnshire - Holbeach	25 Jun
Nottingham - Stubton	20 Jun
Lancashire, Southport	26 Jun
Yorkshire, York	27 Jun
Perthshire, Scotland	5 Jul