Growers and others should be aware of several important issues that were discussed by the Penn State Extension vegetable, berry and mushroom team during this week’s conference call.
Allium leafminer damage to onions and garlic.
This was the most common issue by far and is being seen in central and south-central PA in addition to the southeast now. Reports of “onion maggots” are also coming in from garden centers – these are probably not the Delia antiqua onion maggot, and are more likely the allium leafminer. Adult flight of allium leafminer is over, but feeding signs and larval mines are present. Detection is more difficult on onions than it was earlier in the season, as symptoms of damage are now lower on the plants and hidden by foliage. Damage to bulbs will occur where the larvae have established, so growers will need to cull infested bulbs during and after harvest. Secondary rots are likely to move in when bulbs are damaged. While there is no efficacy data due to the recent arrival of this pest, systemic insecticides such as Exirel and/or Scorpion may provide some control if applied to infested onion and garlic plantings soon, as the odds of control decreases as the larvae move further into the bulbs, or secondary rots occur. An update with photos can be found here: http://extension.psu.edu/plants/vegetable-fruit/news/2017/allium-leafminer-spring-update-may-30-2017
Slow growth and light color of field plantings due to cool wet conditions.
This is common across the state. Plants will green up and grow faster again once we get some sunshine.
Diseases on high tunnel tomatoes.
Botrytis (gray mold) is present on high tunnel tomatoes due to the cloudy cool weather. Timber rot (Sclerotinia white mold) is also present. It is important to remove infected plants before the sclerotia (overwintering survival structures) develop in the stems and fall into the soil where they can persist for years.
Orange rust on black raspberries and blackberries is very common this year.
More information on symptoms and management measures can be found in these two articles: http://extension.psu.edu/plants/vegetable-fruit/news/2017/managing-orange-rust-in-a-bramble-planting and http://extension.psu.edu/plants/tree-fruit/news/2016/orange-rust-on-brambles2014an-ongoing-saga
Late blight on potato is suspected in two counties in eastern North Carolina.
Samples have been sent for confirmation and genotyping. The recent cool and wet weather has been favorable for late blight. Although there were no reports of late blight in Pennsylvania last year it is still important to scout higher risk areas of the field and cull piles for symptomatic volunteers.
Other less widespread issues reported include herbicide phytotoxicity in various crops including Sinbar injury on newly-planted strawberries, excess nitrogen in high tunnel tomatoes, white rot on garlic, cucumber beetles on cucurbits, and botrytis and anthracnose on strawberries.
From Penn State Extension