New Insecticides Greatly Improve Grape Insect Management


The grape berry moth is an annual problem on about 50% of the grape acres around the Great Lakes in New York, Ohio, Pennsylvania and Michigan. Females glue their eggs on the berries and larvae hatch out and feed in the berries. Insecticides have been used for 100 years to control the grape berry moth and reduce the infestation from 24-30% to less than 1%. Until recently, broad-spectrum insecticides with long residuals were used to manage grape berry moth. However, new insecticides have been registered and they provide tremendous opportunities to selectively manage insect pests in grape vineyards.

“The past 10 years has seen a dramatic change in the spectrum of insecticides available for grape producers, with new modes of action and pest spectra allowing an unparalleled opportunity for growers to target specific pests for control while also minimizing the risk to non-target organisms.

There is now increased potential for realizing integrated control, since many of the most effective new insecticides have been evaluated and shown to have relatively low impact on natural enemies. For example, registration of the insect growth regulator insecticides methoxyfenozide and diflubenzuron for use in vineyards and the recent availability of the diamide insecticdes rynaxapyr and flubendiamide allow more selective and long-lasting control of lepidopteran pests without high levels of natural enemy mortality.

Acaricides have also changed from broad-spectrum to more selective chemistries. The vineyard manager now has an array of different acaricide modes of action available, many of which can selectively kill pest mites without injuring predatory species. Some of these are also systemic, thereby providing a route of exposure that further protects predators from direct contact with the acaricide.”

Authors: Isaacs, R., et al.
Affiliation: Department of Entomology, Michigan State University
Title: Vineyard IPM in a changing world: adapting to new pests, tactics, and challenges.
Source: Anthropod Management in Vineyards: Pests, Approaches, and Future Directions. 2012. Springer. Pgs. 475-480.

Good News for Organic Apple Growers: An Insecticide that Kills the Flea Weevil

Weevil damage

Apple Flea Weevil damage

In 2008, the apple flea weevil emerged as a serious pest in Michigan’s organic apple orchards with some growers experiencing >90% crop loss. The organic apple growers were spraying insecticides later in the season to kill major pests like the codling moth and the flea weevil emerged as an early season pest. The weevils feed on developing buds and leaves. Heavy populations cause significant defoliation of leaf tissue resulting in a lacelike pattern which leads to decreased productivity and possible tree death. Research at Michigan State University led to a solution for the organic growers- spray an insecticide…..

“Organic apple growers in the Midwest appear to have a relatively simple solution to their problems with apple flea weevil, which appeared suddenly as a problem in Michigan two years ago and took out 90 percent of the fruit in some orchards.

The best solution, entomologists say, is to spray Entrust (spinosyn) very early in the season, at green tip to pink… The apple flea weevil adult does its most serious damage by feeding on and destroying fruit buds before they have a chance to emerge in the spring.

John Pote, a graduate student at Michigan State University working with Dr. Matt Grieshop and Dr. Anne Nielsen in the organic pest management laboratory, gave the good news to organic growers during a session at the Great Lakes Fruit, Vegetable, and Farm Market Expo in Grand Rapids, Michigan, in December.

Pote noted that the weevil emerged as a problem for organic growers, who normally do not apply insecticides that early in the season, since few insects become active so early.

In conventional apple management programs, the weevil is likely incidentally controlled by insecticide applications made to kill other insects either in April—when overwintering weevils emerge—or in early July—when the summer generation emerges from leaf mines.”

Author: Lehnert, R.
Affiliation: Writer.
Title: Organic control for flea weevil.
Source: Good Fruit Grower. March 15, 2012. Available:

Michigan Tart Cherry Orchards Rely On Fungicide Protection Every Year

Cherry Leaf Spot Infection

Cherry Leaf Spot Infection

Michigan is the leading producer of tart cherries in the United States, with annual yields of 90.9-127.3 million kg, which represents approximately 75% of the total US production.

Leaf spot is the most important fungal disease of cherry trees in Michigan. The appearance of numerous spots on the leaf is usually followed by rapid yellowing and dropping. In experiments, it has been demonstrated that poor control of leaf spot can result in 72% of the tree branches dying during the winter months.

“Cherry leaf spot (CLS) is the most damaging pathogen of tart (sour) cherry trees. All commercial tart cherry cultivars grown in the Great Lakes region of the United States are susceptible to CLS, including the widely grown cultivar Montmorency, which accounts for more than 90% of the tart cherry acreage in Michigan. Left unmanaged, CLS infection causes significant defoliation by mid-summer, resulting in fruit that is unevenly ripened, soft, poorly colored and low in soluble solids. Early defoliation also delays acclimation of fruit buds and wood to cold temperatures in the fall, increases tree mortality during severe winters and reduces fruit bud survival and fruit set the following year.

The almost complete reliance of the tart cherry industry on the cultivar Montmorency has driven a strict dependence on fungicides for disease management. Typically, 6-8 fungicide applications per year are required, beginning at petal fall and continuing through to late summer after harvest.”

Author: Proffer, T. J., et al.
Affiliation: Michigan State University
Title: Evaluation of dodine, fluopyram and penthiopyrad for the management of leaf spot and powdery mildew of tart cherry, and fungicide sensitivity screening of Michigan populations of Blumeriella jaapii.
Source: Pest Management Science. 2013. 69:747-754.

More Sugar from Michigan Thanks to Fungicides

Fungicides: Used (left); Not Used (right)

Fungicides: Used (left); Not Used (right) (Rhizoctonia Control)

Rhizoctonia root rot is a serious disease problem in several sugarbeet-growing regions, with the result sometimes being dramatic—and expensive—reductions in tonnage and quality. Low levels of infections can easily cause yield losses in excess of a ton per acre while high infection levels can cut yields by more than 10 tons per acre. The quality of surviving beets can also be impacted, sometimes resulting in significant losses in recoverable sugar.

“During 2009 and 2010, the Michigan Sugarbeet Advancement Initiative established a study to determine the efficacy and economic impact of various application strategies for the use of Quadris flowable fungicide to control Rhizoctonia root rot.

On average (four trials in each of two years), even with low to moderate levels of Rhizoctonia infection, the per-acre net return of Quadris over the check trials ranged from $94 to $209, depending on the rate, timing and method used. The best treatment in these trials improved recoverable sugar per ton by 14 pounds and percent sugar by 0.7%. Even the “worst” treatment increased RST by 8 pounds and sugar content by 0.3%.”

Authors: Poindexter, S., and Wenzel, T.
Affiliation: Michigan Sugarbeet Advancement, Michigan State University
Title: Rhizoctonia control with quadris—update on Michigan research.
Source: The Sugarbeet Grower. April/May 2011. Pgs. 16-17.

Carrots are Unharvestable Without Fungicide Use

Unharvestable Carrots

Harvesting Carrots

Alternaria leaf blight is the most common foliar disease of carrot. Under optimal conditions, severe foliar epidemics rapidly develop, leading to loss of foliage and reduced yields. Alternaria also indirectly reduces yields by interfering with mechanical carrot harvests. Leaves weakened by blight break off when gripped by a mechanical harvester and the roots are left behind in the ground.

“Because high humidity and frequent rainfall or irrigation is common during the growing season, yield-threatening foliar blights are a recurring problem for carrots. …Michigan growers harvest carrots mechanically and weakened foliage can disrupt harvest due to carrot tops breaking off during lifting. In situations where foliar disease is severe and not controlled, the tops may be compromised to the extent that the crop cannot be harvested. Therefore, fungicides currently play a critical role in the management of foliar diseases.”

Author: Hausbeck, M.K.
Affiliation: Michigan State University, Department of Plant Pathology
Title: Carrot Disease Update
Source: Carrot Country. 2012. Summer:6-8.

Consumers Don’t Want Bugs with Berries, Making Insecticides Necessary

Japanese beetles are often present in blueberry fields and are collected along with the berries at harvest. Because of zero consumer tolerance for bugs in blueberry products, insecticides are necessary to remove the beetles from the blueberry fields before harvest.

“The Japanese beetle, Popillia japonica Newman, is an invasive pest of fruit and vegetable crops, turfgrass, and ornamentals in eastern and central North America. … During the adult emergence period of June to September in Michigan beetles can be observed feeding and mating in clusters on host plants.”

“Much of the food industry maintains a zero tolerance standard for insect contamination at pack-out, which places added pressure on growers of fruit crops such as cherry, peach, plum, and blueberry that may be harvested when beetles are present. The majority of commercial blueberry producers use over-the-row mechanical harvesters for collecting fruit from their fields. This harvesting method does not effectively discriminate between beetles and berries, so adult Japanese beetles are a significant contamination risk in fields being harvested where Japanese beetle has not been controlled.”

“Color sorting technology has been adopted by many large processors to detect and remove beetles, providing >95% removal. Even with these management components available to help minimize the risk of fruit contamination with adult beetles, conventional insecticides remain the primary approach to in-field management of Japanese beetles in fruit crops.”

Authors: J. Wise¹, C. Vandervoort² and R. Isaacs¹.
Affiliation: ¹Department of Entomology, Michigan State University; ²Pesticide Analytical Laboratory, Michigan State University.
Title: Lethal and sublethal activities in imidacloprid contribute to control of adult Japanese beetle in blueberries.
Publication: Journal of Economic Entomology. 2007. 100(5):1596-1603.