Look out for two new pests

Article taken from the Agronomist & Arable Farmer, written by Rachel Anderson

Top fruit growers need to vigilantly look out for two new fruit pests – the spotted wing drosophila (SWD) and the brown marmorated stink bug (BMSB) – this coming season.  They also need to better communicate with one another to help tackle SWD, which hit cherry crops for the first time last year.

These were the warnings given to delegates at Agrovista’s annual top fruit seminar – held at Brand’s Hatch, Kent, on 10th February – by fruit experts Professor Jerry Cross and Alex Cooke.

East Malling Research scientist Jerry Cross revealed that, after arriving in the UK in 2012 and damaging soft fruit crops, SWD caused some end-of-season damage to cherry crops last year.  He said:  “In one day I had five phone calls from different growers saying they had serious problems.  Fortunately, it was the last week or two of harvesting so it was not too much of an issue.”

Good Orchard Hygiene

He told delegates at the seminar that the most effective ways in which growers can control the pest are good orchard hygiene practice and routine pesticide spraying.  He said “It you leave waste fruit on the ground and it is infested, this will cause a storm of an infestation for your later varieties.  It’s so important to put the fruit in a bin and seal it in anaerobic condition.  If you don’t do that then the later crops will be severely affected.”

Mr Cross also emphasised that the best way to monitor SWE and find out if the fly has invaded an orchard is by using the ‘crush test’.  Traps are used around fruit crops throughout the year to monitor the presence of the pest, but, warned Mr Cross, they tend to become less effective when the fruit arrives on the tree.

He said: “Too much effort is given to adult monitoring and it’s giving growers a false sense of security as monitoring traps become less efficient when they start to compete with a crop.  What you need to be doing is monitoring the orchard every week for SWD larvae using the crush test.”

Mr Cross explained that the crush test is a simple process that involved putting the fruit into a polythene bag and then adding a sugar solution to the bag to see if any larvae crawl out of the fruit.

He said:  “There’s going to be an HDC (Horticultural Development Company) video coming out soon, showing growers how to do this.”

Vulnerable Places

Mr Cross advised growers to scale back the number of monitoring traps they use to just a few in “vulnerable places” and to put more effort into larvae monitoring.”  He said: “Adult traps will tell you what’s happening in general, but if, for example, we had just had a cold winter we would know that there was a lower risk that season anyway.”

Agrovista’s fruit agronomist Alex Cooke agreed that larvae monitoring is key.  He told growers that Tracer and Hallmark are the best available products for treating the pest – but that these can both be damaging to beneficial insects.

Mr Cooke also appealed to growers to communicate with one another this year to help tackle the pest.  He said: “It was incredible how quickly it came into orchards last year.  We are all aware of it and we all need to work together.”

He added that there is a lot of work going on in the background to try to get more chemical actives approved for treating the pest, and warned growers to be on the lookout for the BMSV, which as already caused severe problems in the top fruit-growing regions of the US.  Large numbers of the bug have also reached southern and central Europe.

Mr Cross also revealed that the damaged caused by the BMSB resembles that of stony pit.  He said the bug is not yet a problem in the UK but is difficult to control with insecticides. 


18 March 2015

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