Spotted Wing Drosophila – End of Year Round Up – Jim Jasinski & Celeste Welty

Autumn is slowly closing the curtain on most fruit and vegetable production and their associated insect pests, which brings a collective sigh of relief from growers across the state. However, the spotted wing Drosophila (SWD) is one of those pests that is really poised for population explosion, especially in abandoned small fruit plantings that are no longer being treated with an insecticide, high tunnel strawberry crops, and even vineyards that have not been picked yet. For growers needing to treat in high tunnels, remember that Assail, Diazinon, Exirel, Radiant, and Delegate cannot be used in these structures.

Although there are only a handful of county sites still monitoring for SWD around the state (Franklin, Greene, Clark, Clinton, Warren, and Geauga), anywhere there is a baited trap hanging in a field, adult SWD flies are being caught. For example, in abandoned blackberry, red raspberry, and vineyard plantings that still have some fruit, individual trap catches this week ranged from 2 to 590 flies! So, despite it being the end of the season for most pests, if growers are still trying to harvest fruit to take to market, it is recommended that you keep up your spray schedule until harvest is complete.

Even after a hard frost, with temperatures rebounding into the 40’s, 50’s, and 60’s F during the day, some of these flies can escape being frozen to death and remain actively seek fruit to oviposit and damage.

Looking toward next year, research has shown that proper pruning to open up the canopy will allow better control of SWD when applying insecticides. Aggressive pruning will also allow for increased SWD control but at the expense of yield due to reduced canopy.

Pumpkin Disease Diagnosis Field Night at Piketon Oct 5

Coming up in just 2 weeks…

We will be hosting a Pumpkin Disease Diagnosis Field Night on Thursday, October 5, 2017. This field night will be focused on various types of diseases and will be held partially in our pumpkin research field.

If you are a pumpkin grower, or thinking of growing pumpkins, then you will want to attend this educational field night.

The workshop will include the following:
*Pumpkin crop management
* 30 Pumpkin cultivar evaluations
* Disease control and management
* Disease screening for powdery mildew, downy mildew, anthracnose and white speck
* Walking tour of our pumpkin field trial
* And more!

Registration is required, and the deadline to register is October 4, 2017.
OSU South Centers
1864 Shyville Rd.
Piketon, OH
Cost: $10.00
(includes a light meal)
To Register:
Contact Charissa Gardner
at or
at 740.289.2071 ext. 132



Surge in stink bug activity

Since the current heat wave began last weekend, we have been seeing a large increase in stink bug sightings in central Ohio. Stink bugs have not been commonly found for most of the summer even in known hot spots like Columbus. We are now finding stink bugs in late plantings of sweet corn (Figure 1), where their feeding results in shriveled kernels (Figure 2). We are also seeing them in bell peppers and apples (Figure 3) and soybeans , as well as around buildings. Most are the brown marmorated stink bug, but we are also finding some of our native green stink bug and brown stink bug. In soybeans last week, the majority of stink bugs that we found were large nymphs (Figure 4), with only a few adults, but in the past few days we are starting to see fewer nymphs and more adults. It is the new adults that are quite mobile that will be seeking protected places to overwinter. They are particularly active when temperatures are above 80 degrees, as they have been for the past week. Our trapping network has shown that stink bug activity is highly variable around Ohio; there are a few hot spots such as Columbus, but some locations have had no detection of stink bugs, and many locations with only light detection. Reports on catch of brown marmorated stink bug in our trap network can be found with this link: . Growers with susceptible late-season crops should scout their fields to determine whether stink bugs are present.

Figure 1. Brown marmorated stink bug, nymphs and adults, on sweet corn ear.

Figure 2. Shriveled kernels of sweet corn caused by stink bug feeding through the husks.


Figure 3. Adult of brown marmorated stink bug on apple.


Figure 4. Nymph (immature stage) of brown marmorated stink bug on soybean.


Experiments in Vertical Gardening

This video details the progression of vertical gardening experiments at The Children’s Educational Garden at the Hocking County fairgrounds from May through August.  Its lighthearted nature reflects its target audience but the technique is applicable for all ages of gardener.

Late Season Insect Pests of Pumpkin – Jim Jasinski & Celeste Welty

Growers have another 5-6 weeks to protect their pumpkin crop from insect pests such as squash bugs, spotted and striped cucumber beetles, and possibly aphids.  Read the guidelines below for tips on how to manage these late season pests.

Squash bugs – These brown adults and gray nymphs are true bugs that have been slowly building in number through the summer and now seem to be everywhere in the field. They have sucking mouth parts, and feed by piercing the stems, petioles, leaves and fruit trying to get a meal. The time is past for spreading any diseases but in large numbers they can damage fruit and collapse foliage. Thresholds to control these bugs vary by stage but generally more than 1 egg mass per plant or more than 1 adult per plant can be used. Nymphs are generally easier to kill than adults but treatment is only recommended if squash bugs exceed the threshold. See insecticide options at the end of the article.

Adult and nymph squash bugs on handles, fruit, and foliage.










Striped and Spotted Cucumber beetles – These black and yellow striped or spotted beetles have been quietly residing in pumpkin and squash flowers for most of the season, but now that the fruit is maturing, fewer flowers if any are being produced. Beetles are now moving from the flowers back into the canopy and onto the fruit, where they can feed on the rind and the handles, causing significant cosmetic damage. To protect the quality of the fruit and handles, foliar insecticide applications should be made only if beetles are seen actively feeding and scarring the rind.  See insecticide options at the end of the article.

Spotted cucumber beetle.

Striped cucumber beetle.

Cucumber beetle feeding damage on rind.



















Aphids – These small soft bodied sucking pests usually move into fields in mid to late August, and can be found on the lower leaf surface. As a consequence of treating for cucumber beetles and squash bugs, a rapid increase in aphids may be seen when foliar insecticides are used, as most broad spectrum insecticides knock out natural enemies of aphids such as ladybeetles, parasitoid wasps, green lacewings, etc. When large aphid populations inhabit a field, production of honey dew and subsequent blackish sooty mold can be found on the pumpkins. The sooty mold can be wiped off and does not damage the fruit.

Sooty mold on pumpkin fruit.









Products used to control squash bugs, cucumber beetles, and aphids can be found in the Midwest Vegetable Production Guide chapter on Pumpkin (

Getting to the Root of the Matter: Soilborne Diseases of Tomato

It is often easy to tell if a plant is sick when it is covered in spots or leaves and fruits are rotting away, but it can be much more difficult to tell when a plant has an infection in its roots or stems. These lower portions of the plant are essential for health and productivity, but are often attacked by pathogens that reside in the soil. Below are some of the most important soilborne diseases of tomatoes and methods for managing them.

How to identify soilborne diseases of tomato

V-shaped necrosis and yellowing of leaves characteristic of Verticillium wilt.

In general, some clues that indicate if a tomato has a soilborne disease includes stunting, wilting, yellowing, dieback and reduced yield. These are also symptoms of nutrient deficiencies and some viruses, so it is important to rule out these possibilities.

Verticillium wilt: Distinctive V-shaped lesions form on the edges of leaves, with V-shaped dead tissue surrounded by a yellow halo. Plants wilt and have yellowing and dieback. Plants may wilt during the day and recover overnight. The inside of the stem has brown discoloration.

Tomato plant with Fusarium wilt. Note the yellow discoloration on only half of the plant.

Fusarium wilt: Plants have yellowing, dieback, and wilting. Sometimes only half a leaf or leaves on only one half of the plant turn yellow and die. The inside of the stem has brown discoloration near the soil line and discoloration may continue up the stem. Roots may look brown and rotten.

Corky root rot: Plants may appear slightly yellow and have weakened growth. Roots appear to be dry, brown, and cracked and have a similar appearance to tree bark. Cracked areas usually occur in distinctive bands and may be swollen. Dark brown cracking may occur on the crown and taproot of the plant.

Black dot root rot: Roots are discolored, usually a honey-brown to grayish-brown, and are speckled with black dots.

Root knot: Roots are misshapen with small to large nematode-induced galls. Galls may range in size from pin-head to finger-sized. Golden-brown dots (egg masses) may appear on the outside of galls. Plants may appear stunted and weak.

Roots with severe corky root rot. Note the cracked, corky, bark-like roots.

Roots with sclerotia of Colletotrichum coccodes, the causal agent of black dot root rot. The honey brown discoloration is also characteristic of this disease.


Tomato roots with severe root knot nematode galling.

What causes these diseases?

Verticillium wilt is caused by the fungus Verticillium dahliae, which has an extremely broad host range. There are two races of V. dahliae that infect tomatoes.

Fusarium wilt is caused by the fungus Fusarium oxysporum f. sp. lycopersici and there are three races that infect tomatoes. The pathogen is an excellent soil survivor.

Corky root rot is caused by the fungus Pyrenochaeta lycopersici and survives in soil via microsclerotia that form on roots.

Black dot root rot is caused by the fungus Colletotrichum coccodes, which also causes anthracnose on tomato fruits. The pathogen is capable of surviving in soil by microsclerotia that form on infected fruit and roots (the black dots).

Root knot nematodes belong to the genus Meloidogyne. Both the northern root knot nematode (Meloidogyne hapla) and southern root knot nematode (Meloidogyne incognita) are present in Ohio tomatoes. In general, M. hapla forms smaller, distinct galls on tomato roots, while M. incognita tends to form larger, fused and malformed galls. Both species of nematodes have extremely broad host ranges.

How can I manage these diseases?

When managing soilborne diseases, growers should combine management practices that prevent existing soilborne pathogen populations from increasing with practices that actively reduce pathogen populations in the soil.

  1. Prevention: For transplant production, always use clean planting materials including seed, soilless media (recommended) and well or “city” water for irrigation. Ensure that seedlings are healthy before transplanting. Maintain proper fertility and watering to ensure healthy seedling development and maintain adequate nutrient and water levels throughout crop development.
  2. Sanitation: Remove diseased plants and diseased plant parts. Clean soil from boots and equipment between fields and high tunnels. Do not move from soilborne disease-affected fields to non-affected fields.
  3. Rotation: Rotate out of the same plant family when possible. For pathogens with extremely wide host ranges, such as Verticillium sp. and Meloidogyne spp., it is difficult to rotate to a suitable non-host crop. Since most soilborne pathogens are excellent soil survivors, rotations of 3-5 years are usually necessary to reduce pathogen populations adequately.
  4. Host resistance and grafting: Resistant varieties should be selected whenever possible and resistance to Verticillium wilt and Fusarium wilt is incorporated into most modern tomato varieties. Grafting a disease susceptible scion onto a disease resistant rootstock can reduce damage due to soilborne diseases. Many commonly used rootstocks have resistance to Verticillium wilt, Fusarium wilt, corky root rot, and some resistance to root knot nematode.
  5. Soil disinfestation: Several soil disinfestation options are available that vary in cost, efficacy, and environmental impact. Chemical fumigation and steam sterilization are two options that have been used historically, but are often not feasible for use on vegetable farms. Anaerobic soil disinfestation is a newer method of soil disinfestation that involves amending, saturating, and tarping soil. Soil solarization uses solar-generated heat trapped under plastic sheeting to kill soilborne pathogens, but this technique is not often effective under Midwestern conditions. Soils can be flooded or left fallow to kill pathogens over a period of time, but these methods are often ineffective due to the survival structures of most soilborne pathogens.
  6. Chemical or biological control: Few options are available and many biological control options are still experimental.

Article contributed by Anna Testen and Sally Miller, The Ohio State University Department of Plant Pathology


Downy Mildew Confirmed in Pumpkin and Zucchini in Ohio

Zucchini leaf with severe downy mildew. Small blocky lesions are yellow initially, then turn brown as leaf tissue dies. Diseased areas merge and eventually entire leaves die.

While we suspected that downy mildew might be present in southern or central Ohio based on weather conditions, storm trajectories and outbreaks in other states, we had not confirmed it until this weekend in pumpkins and today from zucchinis. The Pike County pumpkins were in a cultivar evaluation trial at the OSU-OARDC South Centers near Piketon. The zucchinis came from two organic farms in Guernsey County. The organic growers indicated that they had observed downy mildew symptoms about 2 weeks ago.

None of the fields had been treated with fungicides effective against downy mildew. As you can see in the zucchini leaf photos in this post, downy mildew can be very severe on squash; similar symptoms can occur on pumpkins. Fungicides should be applied before symptoms are observed – recommended fungicides can be found here.

Organic growers have limited options for downy mildew management. OMRI-approved copper-based fungicides are somewhat effective if applied preventatively. In the chart below, you can see that control varies by year –  in this case good in 2014 and poor in 2013. In both years, downy mildew was significantly less severe in cucumbers treated with Champ WG, oxidate or neem oil  than in non-treated control cucumber plants. Since these are all protectant fungicides, it is critical that they be applied before plants are infected with the downy mildew pathogen. In a separate study conducted at the University of Maryland (Everts & Newark, Plant Disease Management Reports 8:V210), Champ WG alternated with Serenade Soil or Actinovate was as effective as Champ WG alone in reducing downy mildew severity in both cucumber and muskmelon.

Click on chart to enlarge.