IPM Scouting Report: Week of August 17-21

General Comments:  A common condition affecting fruit, vegetables and agronomic field crops is dryness. The Wayne County area needs rain. This past week despite what looked like a promising forecast for several days of rain, we ended up with only about 0.25 inches. Scouts noted moisture stress symptoms in any crops that were not under irrigation during this past week.

Fruit:

Apples are maturing and some are ready for harvest. Once again this past week codling moth trap numbers have remained high in pheromone traps in orchards not using mating disruption. Other insect pests noted on scouting reports include green apple aphids, European red mites, 2-spotted spider mites, and Japanese beetles.  As some apple varieties near harvest, growers need to be vigilant about reading labels and watching pre-harvest intervals if they need to treat for codling moths or any other insect pest.  Disease-wise, most growers have done an excellent job of keeping up and maintaining fungicide spray programs and scouts are noting very little disease. There have been a few apples with some fly speck and some apples with white rot symptoms.

Oriental fruit moth trap captures remained high again this past week in pheromone traps. Growers need to be on a regular spray advisory to prevent damage from OFM larvae, but need to watch labels for pre-harvest intervals as many peaches are currently being harvested.  In addition, spotted wing drosophila (SWD) traps placed in some peach orchards did capture some SWD this past week.

In small fruit, spotted wing drosophila (SWD) trap capture numbers have been increasing in control traps placed near wild fruit that is not being treated with insecticides. These traps have captured close to 100 SWD this past week. Where growers are spraying on a consistent basis, fruit is protected and generally trap numbers are 0 or possibly with 1 or 2 SWD captured. Some raspberry and grape traps recorded 70 or more SWD this past week and growers are being advised to get on and maintain a consistent spray program.

Vegetables:

Lack of rainfall is becoming an issue, especially in larger fields without irrigation or in any smaller plantings without irrigation and scouts noted moisture stress symptoms in some plantings.

Tomatoes are being harvested. Scouts continue to see septoria leaf spot, and early blight in both field and high tunnel production. (See photo below) On the positive side, our current dry weather is slowing the spread of these diseases and later plantings look much better than early plantings. Many field grown tomatoes also have bacterial diseases and scouts continue to note yellow shoulder.  In high tunnel production leaf mold continues on some farms and late blight is showing up in a few high tunnels as well along with powdery mildew.  Scouts continued to find tomatoes with stink bug stings in both field and high tunnel production tomatoes.  Aphids are being seen in some high tunnels as well.

Cole crops planted for fall harvest continue to have pressure from imported cabbage worm with many plantings above treatment threshold levels. Some plantings also had flea beetles at treatment threshold levels.  An outbreak of zebra caterpillars in one field was causing some localized heavy feeding damage.

Depending upon the planting date, vine crops range from bloom to harvest. There is a lot of cucumbers, summer squash, zucchini, and melons (cantaloupe and watermelon) currently being harvested. Powdery mildew is being found by scouts in virtually every planting and growers are being advised on maintaining a fungicide spray program to minimize damage from this disease.  Downy mildew has been found in a number of cucumber plantings and some growers have been able to greatly slow or even arrest the development of the disease with a good fungicide spray program and some help from recent dry and hot weather conditions.  Downy mildew has also been found in some plantings of cantaloupe and that disease is now beginning to show up in some squash plantings as well.  Anthracnose and angular leaf spot are also commonly noted by scouts in many melon and fall squash and pumpkin plantings.  Plectosporium blight has been found in several pumpkin plantings as well and symptoms of the disease are showing up on some of the ripening pumpkin fruit. (See photo below)  Other diseases that have been noted, but that are not widespread, include phytophthora fruit rot, fusarium fruit rot and septoria leaf and fruit spot. (See photo below)  Insect-wise, cucumber beetles continue to be present at anywhere from light to threshold or above numbers and some damage by cucumber beetles chewing on the rinds and stem handles of squash were noted by scouts.  Some fields had localized heavy infestation of squash bugs. Eggplant and pepper fruit are being harvested. Sunscald is being noted on both crops by scouts on a frequent basis. Many of those sun scalded fruit are developing secondary botrytis infections.  Anthracnose has been found on both leaves and fruit.  Alternaria was also noted by scouts in both peppers and eggplant this past week.  Some fusarium wilt on eggplant was noted this week along with some bacterial soft rot in peppers.  In some eggplant plantings Colorado potato beetle numbers were at treatment threshold levels. In peppers, some growers are treating for European corn borer (ECB) larvae to prevent damage, and ECB moth numbers in pheromone traps averaged 9/week, so growers do need to be treating to prevent damage. Stink bug stings have been noted on fruit by scouts along with the presence of aphids and grasshoppers.

Green snap beans range from in bloom to harvest. Scouts have not noted any disease problems in green beans.  This past week the greatest damage was coming as a result of ground hogs and deer feeding on the crop.

Sweet corn ranges from plants at V-7 to harvest. Corn earworm trap numbers remain very low, 0 in traps at 4 locations this past week. European corn borer moth captures ranged from 0 to 7 at 4 locations. Scouts noted some damage to ears from European corn borer larvae and damage to sweet corn plants from fall armyworm as well as some silk clipping due to Japanese beetle feeding. Rust and Northern corn leaf blight were noted on the lower leaves of some plantings. Much of the sweet corn, if not irrigated, is showing drought stress.

Potato harvest is underway in many plantings or plants are drying down so insect and disease monitoring has ended on this crop.

Bacterial disease on tomato

Bacterial disease on tomato, by Kate Fike

Plectosporium blight on pumpkin

Plectosporium blight on pumpkin, photos by Chris Smedley

Septoria on squash fruit

Septoria on squash fruit, photo by Chris Smedley

Agronomic Field Crops:

Scouting has ended on a lot of field corn as corn enters the R3-R4 stage of development. In some later plantings corn rootworm beetles and some Japanese beetles have been noted.

Soybeans range from R-4 to R-7. Some fields continue to show defoliation at 10-20% due to a combination of feeding by grasshoppers and Japanese beetles. Aphids remained at low levels this week.  Stink bug numbers increased in some fields, actually reaching threshold levels in one location. Scouts are noting that soybeans are under moisture stress and some pods are being aborted. (See photos below)

Alfalfa regrowth following 3rd cut harvest is slow, due to the current dry conditions. Fortunately potato leaf hopper numbers remain very low and are not causing additional stress to alfalfa plants. Other insects being noted by scouts in alfalfa include grasshoppers, aphids, plant bugs and loopers.

Drought stress, soybean plants

Drought stress, soybean plants, photos by Art Sigler

Soybean pods affected by lack of rain

Soybean pods affected by lack of rain Photos by Art Sigler

 

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