Brown Marmorated Stinkbug: Risk of Agriculture Damage is Coming Closer
Crop damage from Brown Marmorated Stinkbug (BMSB) is getting closer to us, so we may soon begin to experience it ourselves. In 2013 & 14, it was reported in the lower Hudson River Valley of New York. My colleague Mary Concklin (University of Connecticut Cooperative Extension) reported that there was BMSB damage in Connecticut orchards in 2015, especially at one site where a number of apple bins had been transported from the lower Hudson River Valley (probably carrying some BMSB’s). BMSB’s have relatively long mouthparts, about ¼ inch for adults. The insects insert their mouthparts deeply into the flesh of the fruit, then inject saliva into the fruit. The saliva partially digests the flesh, and the insect sucks up the liquid. That means that most of the damage is below the surface, and often the only hint it is there is a slight depression and a minute hole, visible through a microscope. Damage to apples can look like boron or calcium deficiency. In sweet corn, damaged ears look OK until they are cooked, when the affected kernels turn brown.
Here in NH, we have been trapping for BMSB since 2011, using the very best trap & lure combinations available. We finally caught our first BMSB’s in a trap in 2014. Actually we caught two in that trap, which was in Milford. In 2015, we caught 45 adults and 27 nymphs in traps. Traps that did catch some BMSB’s were in Hollis, Brookline, Milford, Litchfield, and Nashua. Most traps in our (multi-county) network caught no BMSB’s, as has been the usual case.
We will keep monitoring. I anticipate that the first crop damage might appear in Hillsborough or Rockingham County. August/September seems to be the time they move into orchards, corn or pepper fields, beginning at the wooded borders. If I had money to bet, I’d anticipate the first NH crop damage would be in 2018, possibly later. By the way… adults are emerging from inside the walls of buildings, and will continue to do so through May, possibly later. So, you could see live adults now, especially in a building.
Exotic BMSB Parasite
Trissolcus japonicus is one of the BMSB bio-control agents that is being studied in the USDA quarantine labs in Beltsville, MD. It is a tiny wasp that searches for BMSB eggs, and attacks them. Is it safe to release in the USDA? Officials haven’t finished examining that question. But the answer might be moot. In 2015 we learned that the species was discovered outdoors in Maryland and Oregon/Washington. My reaction was that it must have escaped from the quarantine facility. No. Researchers analyzed the DNA of specimens from these new sites, and found it did not match the strain being studied in quarantine. They are the same species, but not the same strain. I’m waiting to hear if they will go ahead and allow release of the agent, or if they will finish their testing. One question they ask is whether the parasite will attack eggs of other species, besides BMSB. We would not want to introduce something that might, for example, parasitize eggs of predaceous stinkbugs.
Controlling Mexican Bean Beetles with Metalized Mulches
A poster at the January Northeast Plant, Pest and Soils Conference showed a study of light-reflecting mulches tested for Mexican bean beetle control in snap beans. Such mulches have been tested before. As a college student at the University of Massachusetts I helped with a study of reflective mulches in repelling aphids from squash. They worked. Amy Ouellette studied the yields of tomato with reflective mulch. Now this study from Virginia shows that metalized mulches reduced Mexican bean beetle damage and increased yields, compared to bare soil plots. Of course, these were plots that had significant numbers of bean beetles. If you have problems with MBB in your garden, and don’t wish to use an insecticide, this might be an option to test. Two problems: 1) you’d have to let the soil warm up well before applying the mulch. 2) Some of these reflect sunlight so strongly, you feel like wearing sunglasses to pick the crop. No, that’s not a joke.
New Insecticide for Piercing-sucking Insects that Spread Diseases
Recently my colleagues and I discussed how serious aphids are on brassica crops and spinach. Then, I learned about a new insecticide at the Northeastern Plant Pest and Soil Conference. Flupyradifurone is a new insecticide called Sivanto, from Bayer. It is in a new chemical family, shows translaminar and systemic activity. The manufacturer seems to be targeting it for insects with piercing-sucking mouthparts that spread diseases. Aphids, leafhoppers and a few other pests are on the label. Brassicas, spinach, potato, grape, pome fruit and other crops are on the label. I don’t see bee warnings, but I do see cautions about runoff & water contamination. The CDMS database has the label, which is dated March 2015. That must explain why we don’t have it in the 2014-15 Veggie guide.
Legality of Sulfoxaflor Use
On November 12, 2015, EPA cancelled the registrations of (relatively new) Dow insecticides containing sulfoxaflor (Sequoia, Closer and others). This unusual action occurred as a result of a lawsuit that alleged EPA did not have enough data to have registered these products, when it did a year or more ago. When many of you were harvesting apples, the ninth circuit court of appeals issued their ruling to the EPA (Sept 10, 2015), which forced EPA into its action. My immediate reaction to the November announcement was to ask what would happen to the pesticide that was already sold, and in the hands of growers and orchardists.
The answer is that EPA will allow continued use of such material already in growers’ hands, provided they follow the label. Closer is the product most likely to be familiar to fruit and vegetable growers. A fairly specialized insecticide, it controls aphids, whiteflies, some scales and psyllas. So, you can keep on using it.
Fruit Bud Stages
In Durham and Madbury, McIntosh apple buds were in green tip stage on Monday April 4th. I examined them while standing in a fresh 2” of snow. Blueberry fruit buds have swollen buds, and some varieties have progressed to the loose bud scales stage. Raspberries have about ¼ inch of growth, and thornless blackberries show no movement. Peach flower buds appear dead. It is possible that the low temperatures we had April 3rd & 4th may have damaged some apple buds. On Monday April 11th, the apple buds look virtually the same, but the covers have been removed from the thornless blackberries, revealing about ¼ inch of growth from the buds.
Apple Scab Ascospore Maturation Model
The apple scab ascospore maturation model begins when 50% of the fruit buds on McIntosh are between silver tip and green tip stage. In Durham and Madbury, probably that was Friday April first.
If you had fireblight in your apple orchard last year, consider making a copper spray at silver tip and/or green tip stage. That can kill most fireblight bacteria exposed on the surface, and reduce the chances of more strikes this year. The formulation does not matter. What is important is to apply 1 to 2 lbs of the metallic equivalent per acre. Applying copper past the ¼ inch green stage increases the risk of phytotoxicity. For some of you, it is too late, but we had fireblight strikes reported pretty far north last year, so there may still be time in some spots.
Monitoring Tree Fruit Insects with Traps
If you monitor tarnished plant bug activity in your apple orchard, the time to hang traps is silver tip stage. If you hang them late, it will be hard to use the threshold, which is designed to measure the number of TPB’s starting at silver tip stage. TPB traps are hung at KNEE height, toward the tips of a branch, preferably over a grassy part of the orchard floor. The red sticky rectangular leafminer traps go up at about ¼ inch green stage. They go on the south or southeast side of the trunk, at knee height. Warm, sunny weather will hasten activity of both those insects. Later this week the forecast shows sunshine and milder temperatures… not really warm, though.
Blueberry growers take note: the fungal stipes of mummyberry fungus should be emerging from last year’s mummified berries on the ground. The growth starts as a dark brown spike, then enlarges at the tip to form a mushroom, and lightens in color. In my one of my photos, there are two fungal stalks (stipes), one of which has already has a tiny opening at the tip. In the other, the “mushroom cup” has formed well. They begin releasing spores when the mushrooms are partially open. This usually coincides with the first green blueberry tissue being exposed. Urea sprays are designed to burn off those fungi, and applying a layer of mulch is designed to bury them. For most sites in southern NH, it is a bit late to consider burial by mulch now.
2016 Tree Fruit Management Guide Updates to the 2015 Guide
The New England Tree Fruit Management Guide is a publication produced in collaboration by the Cooperative Extension systems of the Universities of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont.
The most recent printed edition is the 2015 edition. This is available for purchase from UNH Extension (603-862-3200). As of the writing of this newsletter, UNH Extension and Alan Eaton have 7 remaining guides. They are also available from the UMass Bookstore. The cost is $36.
In 2016, instead of printing a new guide, the authors decided to produce a short addendum with know updates and changes where current information differs from the 2015 edition. The 2016 Update to the Tree Fruit Guide is available HERE.
Alan T. Eaton
Integrated Pest Management
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