Cool temperatures during May have continuedto slow crop growth. In wheat the flag leaf has been slow to unfurl allowinggrowers to take a quick breather between sprays.
Spring crops have been particularly affectedby the cool, wet conditions. Sugar beet seedlings are small, backward and proneto bird damage, while slow growing spring rape and linseed are still at riskfrom flea beetle attack.
In wheat disease pressure from septoria andyellow rust remains high and in some circumstances other diseases such asmildew, brown rust and take-all are becoming evident.
By now early-drilled wheats will havereceived a flag leaf spray. When timing the T2 spray, growers should target theunrolling flag leaf rather than setting timings according to the intervalbetween treatments (unless the gap between T1 and T2 is longer than 4 weekswhen a holding spray may be required). Where the T1 was applied late, the gap between treatments may be short.
This season wheat crops will require a robustT3 spray to maximise control of foliar and ear diseases. This should be especially strong ifthere is a long interval from T2 to ear emergence (greater than 4 weeks). Following all this wet, the fusariumrisk will be high, especially if the weather remains unsettled. Milling wheats should be treated atearly flowering.
In rape the extended flowering period meansthat crops are still at risk from sclerotinia. This threat will increase as temperatures warm; some cropsmay require an additional spray to extend the period of protection. Lodged crops will also benefit from alternariaprotection.
In beans chocolate spot pressure is very highand threatens to defoliate plants prematurely. Control with well-timed, repeatedprotectant activity. Dealing with bruchid beetle is notoriously difficult asthe timing of insecticide is crucial to control the adults before egg laying.Improve control by monitoring temperatures as the first pods develop; cropsshould be sprayed when temperatures reach 20°C for two consecutive days.