Black aphids TheBBRO continues to receive telephone calls for the need to control black aphidsin beet. Our recommendation remains unchanged as there is no need to treat forthis pest unless the crop is under stress as seen from previous BBRO-fundedyield trials. There are a plethora of predators and parasites within crops atthe moment doing an excellent job of eating aphids and it is important theseare protected.
Peach-potatoaphids – Trap catches have shown that this species has also increaseddramatically over the last 10 days at certain sites, possibly as winged aphidsmigrate from maturing oilseed rape. The latest insecticide resistance testsmade by Rothamsted Research continue to show very high levels of resistance topyrethroids and pirimicarb. This week the BBRO have undertaken an aphid trialto evaluate a range of aphicides and the first counts will be made on Friday.
The BBRO ispushing for a decision from the regulators as to whether an emergency of labelapproval will be granted for leaf miner control. Latest field reports fromworst affected areas suggest that new (second generation) eggs can be found inincreasing numbers. Control options remain very limited, although new BBRO workwith ADAS continues to assess the efficacy of novel/existing products. As soonas the BBRO learns of any decisions regarding the off-label approval allgrowers and agronomists will be notified.
Silver Y moths
Silver Y mothadults continue to be caught in variable numbers in pheromone traps at BBROmonitoring sites with up to 50 adults now caught at some sites in Norfolk.However, no reports of caterpillar damage have been received. Please continueto evaluate crops as current weather patterns will favour its migration andpotential build up.
Downy mildew isalso being found in crops particularly now that secondary symptoms of leafyellowing are showing. Please continue to send in reports of this problem asthe BBRO is monitoring the extent of the problem and the varieties affected.This week we have established a trial in Cambridgeshire to evaluate threeproducts for its possible control. Again we will report on the progress of thiswork as the season progresses.
Weed beet andbolters continue to emerge above the canopy and will need controlling ifmassive seed return is to be avoided. Weed beet stems are also appearingfrom groundkeepers on old loading sites and land left fallow after beet lastyear. These need removing as well. If spraying fallow land to killany green cover, check the rules relating to crop destruction and try todestroy weed beet before seed set.