Stink Bug Pressure Could Be High This Year
“Every year is unusual, and this year is the same,” Chris Walsh, Professor in the Department of Plant Science and Landscape Architecture at University of Maryland Extension, said as the Regional Spring Orchard Meeting kicked off last week at Orr’s Orchard and Farm Market in Martinsburg, WV.
Extension agents from Maryland, West Virginia, Virginia, and Pennsylvania gave recaps on fruit diseases, monitoring and management of pests, and a general update on the growing season. Orr’s Family Farm is a third-generation farm on approximately 1,100 acres. Typical apple plantings are 10-feet-by-24-feet and still have a strong market for ‘Red Delicious.’
One highlight of the meeting to note is the potential for high numbers of stink bugs this season. Chris Bergh, Associate Professor of Entomology at Virginia Polytechnic University, says USDA-ARS are using overwintering shelters for the brown marmorated stink bug (BMSB) to study the overwintering mortality and emergence of the pest in the spring. Bergh said he found 3,200 BMSBs in one shelter.
“The overwintering survival is higher this year than last,” he says. “A lot more bugs are emerging and surviving.”
At this point in the season, he says there are higher catches in traps than the past two years.
“Pay attention to BMSB this year,” he cautions growers.
Peak emergence for BMSB was early to mid-May, and by the end of June growers should see second instar nymphs.
Greg Krawczyk, Penn State University Extension fruit tree entomologist reminded growers to read the Michigan State University Extension bulletin about pesticide rainfastness. He said this would help growers understand how much rainfall their orchards can sustain before they need to reapply.
“Spotted wing drosophila (SWD) is kind of lazy, like all of us, and they tend to go for the low-hanging fruit,” Tracy Leskey, director of USDA-ARS Appalachian Fruit Research Laboratory in Kearneysville, WV, said on a recap of SWD traps available. Leskey suggests growers place the traps near the outer parts of berry plants.
Mahfuz Rahman, assistant professor and Extension specialist in plant pathology at West Virginia University introduced a new IPM resource for growers called iPiPE, and urged growers to take a survey on IPM practices.
Daniel Frank, assistant professor and Extension specialist for West Virginia University also suggested growers scout for Oriental fruit moth, coddling moth, peach tree borers, and dogwood borer.
Weather Issues And Horticulture
Jim Schupp, Professor of pomology at Penn State University, talked about how the warm early spring, and subsequent cold snap impacted chemical thinning and the carbon balance model for apples.
There was also an extended apple bloom, where Schupp said some growers had a bloom for about 30 days. Growers with this extended bloom experienced a loss of king bloom when the cold temperatures in early April hit.
However, Schupp said that even with a 40% to 60% flower mortality, growers still had 700% to 800% of the apple crop still alive. Schupp said this year was a good time for growers to employ Michigan State University Extension educator Phil Schwallier’s nibble approach to thinning.
“Things are looking a lot better than two months ago,” Walsh said.
Kari Peter, Assistant Professor of Tree Fruit Pathology at Penn State University, says growers still need to scout for apple scab. The worst occurrences were during the rainy and wettest periods this spring. But, she suspects within a week or two, scab infections will be over.
But, Peter says fire blight infections have started and stopped.
“My working hypothesis is it won’t be catastrophic,” she says.
Peters says growers still need to worry about cankers left from last year’s fire blight epidemic, especially if growers did not apply Apogee to the trees.
“You will see shoot blight,” she says.