North Carolina Pest News – July 26, 2013 (Fruits & Vegetables)
NORTH CAROLINA COOPERATIVE EXTENSION SERVICE
North Carolina State University * College of Agriculture & Life Sciences
Departments of Entomology and Plant Pathology * Raleigh, NC 27695
NORTH CAROLINA PEST NEWS
Volume 28, Number 16, July 26, 2013
CAUTION: The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas!
FRUIT AND VEGETABLES
From: Hannah Burrack, Extension Entomologist
End of Harvest Concerns in Blueberries
As blueberry harvest nears the end in North Carolina, a few important insect related issues require some attention.
Spotted wing drosophila in processing fruit
Rainfall makes spotted wing drosophila (SWD) management more challenging (http://strawberries.ces.ncsu.
There are some strategies that growers can employ post harvest to decrease the likelihood that SWD infested fruit will be sent off for processing:
1. Hold fruit at cool temperatures. Work in our lab suggests that SWD eggs and larvae cease development at temperatures less than 41F. They will not necessarily die at cool temperatures, but they likely will not cause further damage to the fruit. The longer fruit are stored and the cooler the temperature of storage, the more likely that small SWD larvae will die. Holding fruit at cooler temperatures also give growers the added benefit of determining how significant the infestation, as large larvae will exit fruit as it cools.
2. Sort out soft fruit. Soft fruit is the most likely to be infested with SWD for two reasons – egg laying SWD are more attracted to soft fruit and blueberries become softer as SWD feed. If growers can remove soft fruit before sending fruit for processing, this will further decrease risk of infestation being present. I suspect our aggressive soft sorting standards for fresh market blueberries are one of the reasons that SWD has been a less significant issue in this crop than some other hosts.
3. Sample collection timing. When receiving fruit, processors can either collect samples before or after fruit are sorted/de-stemmed. Samples collected before fruit has been soft sorted are not necessarily representative of the status of the fruit that will be processed. Samples of fruit after chilling and sorting, prior to processing/freezing, are likely more representative.
Post harvest leafhopper treatments
Treatments to manage sharpnosed leafhopper (http://ipm.ncsu.edu/small_
Aerial applications of ULV (ultra low volume) malathion has been used in the past for leafhoppers due to effectiveness and ease of application. However, many growers have also used this material for SWD management during the season, and careful attention must be paid to label restrictions on the number of applications that can be made of materials when selecting tools to manage sharpnosed leafhopper. Application limits apply to the entire growing season, not just harvest season, so label limits on the number of applications also apply to leafhopper treatments. Application limits apply to the amount of active ingredient, not the trade names of those active ingredients. Sources for updated labels with current use restrictions include CDMS (http://www.cdms.net/Home.aspx
Alternatives to malathion that are effective against sharpnosed leafhopper include Assail (acetamiprid) and Asana (esfenvalurate). Imidaclorprid and thiamethoxam are also options for sharpnosed leafhopper. The North Carolina Agricultural Chemicals Manual (http://ipm.ncsu.edu/agchem/
From: Lina Quesada-Ocampo, Extension Plant Pathologist
Cucurbit Downy Mildew Moves Towards Western North Carolina
Cucurbit downy mildew has been reported in Haywood, Polk, Ashe, Henderson and Chatham counties (http://cdm.ipmpipe.org/
If you are not familiar with cucurbit downy mildew symptoms on different cucurbits please see our previous alert (http://plantpathology.ces.
For more information about the disease and how to control it, see our factsheets in English and Spanish (http://projects.cals.