Garden calendar | For the week of July 29

July 30, 2018

Fruit: After summer raspberries are done fruiting, cut out the floricanes, which are the canes that bore fruit this year, and dispose of them. This will eliminate any over-wintering insects like raspberry cane borers that might have taken up residence from causing problems for you next year. Since these canes are not going to fruit again, it is OK to get rid of them and it also encourages the plant to put more energy into developing primocanes for next year. These primocanes that have not yet fruited will supply you with next year’s crop. Watch for diseased canes that have brown or purple spots on the canes and remove them, disinfecting your shears with rubbing alcohol between cuts. Watch out for infestations of the spotted wing drosophila (SWD) fruit fly in raspberries. This tiny insect is a type of fruit fly/vinegar fly, and can be devastating to raspberry and other soft fruits. It lays eggs in the raspberry fruit just as it is starting to color up, unlike most fruit flies that mostly attack rotted or fermenting fruit. With SWD, by the time the fruit ripens, it is full of hatched-out maggots. Maggot feeding allows in mold spores that then totally destroy the fruit. It has been particularly problematic in fall raspberry production, but now is being found in summer raspberries sometimes as well. The reason this insect is able to accomplish its attack so early in the fruiting cycle is because the females have a serrated ovipositor that allows them to literally saw into unripe fruits and lay their eggs before other species of fruit flies. You can identify SWD by the spot on the wings of the males (females lack the spot). Trapping is a good way to monitor for SWD, though not a good way to control it. Capped plastic cups with apple cider vinegar and one-quarter-inch entry holes and yellow sticky cards inside make good traps. Visit the Plant Disease Diagnostic Clinic website at https://pddc.wisc.edu/ and look under the fact sheets tab for more information.

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