Grower Survey to Assess Herbicide Drift Damage in the North Central U.S.

A special project group of the North Central Integrated Pest Management (IPM) Center wants to learn about your concerns and experiences with herbicide drift. The group is surveying growers of fruits, vegetables, and other specialty crops in the upper Midwest.

To truly understand the frequency, severity, and economic impact of herbicide drift on specialty crops, we need to hear from growers: growers who have experienced drift damage, growers who can share their concerns around this issue, and even growers who have not dealt with drift but who grow sensitive crops in drift-prone regions. Survey responses are needed to establish herbicide drift as a serious economic and regulatory concern in Ohio and across our region.

Please complete the survey at go.osu.edu/drift21.

Who should take this survey?
The study is for commercial growers of fruits, vegetables, and other specialty crops in IA, IL, IN, KS, MI, MN, MO, ND, NE, OH, SD, or WI. Even if you have never experienced herbicide damage, we would still like to hear from you if you grow specialty crops in one of these states.

Why is this survey necessary?
Dicamba and 2,4-D drift damage has made headlines in recent years, but no study to-date has attempted to quantify the overall impact drift has on the specialty crop industry. While all states have a way for growers to file a drift complaint, the process and requirements are inconsistent and may involve time and information that a grower does not have. In most states, for instance, the source of the drift must be identified. Research has found that dicamba and 2,4-D both have the potential to travel for miles in specific weather conditions, making source identification difficult.

What good will this survey do?
This study is designed to assess the potential and actual frequency of drift damage, along with the severity and economic impact of such damage. The survey includes questions on grower awareness, experience, actions, and decisions related to herbicide drift and drift-risk management. The responses will help establish needs for research on drift mechanisms, prevention, and remediation; and/or the need to review current policy and reporting requirements.

How long will it take?
The survey takes 5-20 minutes to complete, depending on your experience with drift damage.

How will this data be shared?
Summarized survey data will be shared broadly with regulatory agencies, university educators and researchers, agricultural policy makers, grower support organizations, and the general public using news articles, report summaries, and peer-reviewed journal articles. While this study is administered by The Ohio State University, it was planned in partnership with industry experts across the region who will assist with sharing results. Participants may also request a copy of the study summary.

How will my data be used and protected?
Your privacy is important. No individual survey data will be released or shared beyond the limited group of project staff. The survey questions and procedures have been reviewed by the institutional review board at The Ohio State University and are designed to protect your data and identity. Additional details on privacy and confidentiality are provided at the beginning of the survey.

How can I learn more?
The North Central IPM Center’s special project group created a series of fact sheets on herbicide drift especially for specialty crop growers. The series includes: Overview of Dicamba and 2,4-D Drift Issues, Frequently Asked Questions, Preparing for Drift Damage, and Responding to Drift Damage. Fact sheets and more information about our special project group and study are available at go.osu.edu/ipm-drift.

This study is facilitated by The Ohio State University and is funded by the USDA National Institute of Food and Agriculture through agreement 2018-70006-28884.This study is being conducted in cooperation with regional universities and non-profit grower organizations, including Ohio State Extension.

Soil Sampling and Analysis for High Tunnel Production

Installing a stationary high tunnel (HT) is a significant, long-term commitment to the parcel of soil beneath it, especially if the crops will grow directly in that soil. Maintaining, and preferably enhancing, the health, quality, or productivity of that soil for as long as possible should be a high priority beginning at HT installation.

Soils in HTs are less well understood than uncovered soils in “open sky”/open field production. However, the HT farming, extension-research, and industry communities are aware that HT soils are prone to specific issues and require specific care to remain commercially viable. These issues and preventative or reclamation tactics are the subject of much research and extension. Therefore, HT growers are encouraged to stay tuned for more information, including on how they can participate directly in identifying concerns and developing solutions. Examples of concerns and working solutions were summarized in a recent presentation (https://www.youtube.com/watch?v=XpUl0IwaDFI). Choosing one concern, in a summary of a presentation given at the 2013 New England Fruit and Vegetable Conference (https://newenglandvfc.org/sites/newenglandvfc.org/files/content/proceedings2013/Hoskins%20High%20Tunnel.pdf), Bruce Hoskins of the University of Maine’s Analytical Lab and Soil Testing Service mentions that the buildup of nutrient salts over time is “one of the most common problems in a continuously covered HT system,” that HT soil management can be similar to “irrigated desert production in the west and southwest,” and that growers familiar with open-field production can “fail to realize this potential problem or take steps to remediate it.” He also mentions that nitrate may carryover from one HT crop cycle to the next more readily than in open field production.

We heard from Bruce Hoskins and John Spargo during recent conversations about HT soil management. They direct soil testing and analytical labs at the University of Maine (https://umaine.edu/soiltestinglab/) and Penn State University (https://agsci.psu.edu/aasl), respectively. Each of these labs receives soil samples from hundreds of HT growers (conventional, organic) each year and have been actively helping improve soil management recommendations and cropping outcomes for HT growers. They have been joined in that work by others, including farmers, across the Northeast and Mid-Atlantic regions for years.

Take-aways from these recent conversations include that routine soil testing is essential, along with accounting for potential nutrient salt buildup when collecting soil samples. Normally, samplers: 1) use a soil probe or spade to retrieve a column of soil about twelve inches deep, 2) drop the soil in a bucket, 3) repeat the process one or more times from other areas, 4) mix the soil in the bucket, and 5) submit a portion of it for analysis. Listening to testing and other experts, the best approach appears to include “stratified” sampling; that is, submitting samples taken from 0-4 inches deep (upper layer of the rooting zone) separately from samples taken from four inches and deeper (lower layer of the rooting zone). Salts tend to accumulate in upper layers, especially if soil is heavy-textured and irrigation is frequent but brief. So, standard “mixed” samples may either: (a) underestimate salt levels in upper layers of soil experienced by roots of transplants and more mature plants or (b) overestimate salt levels if samples include only the upper level. Stratified sampling, mindful that soil characteristics can change with depth, equips growers and others with information to better manage HT soils. Regarding the costs of soil testing, especially of stratified samples, input from soil testing labs suggests that few of the growers they work with mention it as a significant concern. Instead, most growers appear to have done their math and concluded that soil analysis offers a significant return on investment, given that its cost is more than offset by gains in crop yield and quality in the current and subsequent years.

Grafted Plants: What They May Offer You and How to Obtain Them

Grafting creates physical hybrids between seedlings of at least two varieties. The rootstock variety is used for its root system and traits and the scion variety is used for its shoot and fruit traits. Grafting is providing growers with an expanding list of key plant traits more rapidly and in different combinations than standard hybrid variety development. These traits include resistance to specific soilborne diseases (e.g., Fusarium, Verticillium) and the ability to overcome various abiotic stresses (e.g., salinity, drought, low fertility). Plant growth at low soil temperatures, improved fruit quality, and/or greater fruit holding ability on the vine may also be possible in specific cases. Among grafted crops, field and high tunnel acreage of tomato and watermelon are greatest, although interest in and acreage of grafted pepper, eggplant, cucumber, and melon are also rising.

Resources to help growers make the best use of grafting are also increasing and improving. The most important resource is growers who have experimented with grafted plants and share their experiences and views. Online resources (e.g., http://www.vegetablegrafting.org/) can also be useful. For example, one site (http://graftingtool.ifas.ufl.edu/) helps growers “run the numbers” on grafting’s potential impact on their bottom-line. That decision-support tool improves as information from farm-level tests of grafting is added.

Growers also ask how they can obtain grafted plants. The number of operations supplying Ohio and the U.S. (http://www.vegetablegrafting.org/resources/suppliers/) is rising. I have personal experience with the three suppliers listed below in alphabetical order. Contact them soon if you are interested in receiving grafted plants for use in 2021.

1. Banner Greenhouses (Nebo, NC; ph. 828-659-3335; https://www.bannergreenhouses.com/).
2. Re-Divined (Bainbridge, PA; ph. 717.286.7658; grafted@redivined.net; https://redivined.weebly.com/).
3. Tri-Hishtil (Mills River, NC; ph. 828.891.6004/828.620.5020 – Chris Furman; sales@Tri-Hishtil.com; http://www.trihishtil.com/).

Grafted plants can also be prepared by the same person or farm that uses them in the field or high tunnel. Many guides describing how to graft vegetables are available. The following are a small number of examples.

1. https://u.osu.edu/vegprolab/grafting-guide/ and other resources at https://u.osu.edu/vegprolab/research-areas/grafting-2/.
2. http://www.vegetablegrafting.org/resources/grafting-manual/.

Please contact me if you need additional information.

Grafting, In-row Spacing, and Seasonal Nitrogen Application Rate Effects on Watermelon Yield and Quality

Growers, consultants, seed company representatives, and others have questions about watermelon management protocols, especially when grafted plants are used. The three panels below provide background on and summarize preliminary findings from two experiments on this topic completed in Wooster in 2020.

Please contact me at kleinhenz.1@osu.edu or 330.263.3810 for more information.

Wayne County IPM Notes from September 20-26

Vegetable Pests

Aphids feeding on pumpkin leaves. F. Becker photo.

Cucurbit growers need to check their crops for infestations of aphids. Large populations of aphids can be found feeding on the underside of leaves. While the feeding on the foliage is not of major concern at this point in the growing season, the exudate from the aphids is. Aphids secrete a sticky substance known as honeydew and when large amounts of the honeydew are being formed, it can drip down onto the pumpkins and result in black sooty mold growing on the fruit.

Continue to keep watch over late season cole crops as there are still a lot of imported cabbageworm adult butterflies in and around crops such as broccoli, cabbage, brussels sprouts, and cauliflower. Additionally, other fall insect pests such as the cabbage looper and aphids can become problematic. Aphids can have rampant infestations during cooler and dry weather.  Therefore, routine scouting, especially at this time of year, is important to effective pest detection and management.

Imported cabbageworm larva feeding on cole crop leaves. F. Becker photo.

Fruit and Vegetable Diseases

Residue management of fruit and vegetable crops is an important component of integrated disease management. Typically, at the end of the season, plants are commonly being affected by a range of diseases. As management of these diseases dwindles towards the end of the season, there is an increased level of inoculum that may be able to over winter. Many of the pathogens affecting the plants now are able to over winter and result in disease challenges again next year. It is important to know what diseases you have in your fields. This knowledge can help you make crop management decisions such as how long to rotate out of a certain crop. Additionally, the residue that is left at the end of the season should either be composted or tilled into the soil as soon as possible. Composting or incorporating the crop residue allows for the plant to be broken down by soil microorganisms and prevents the spread of the pathogen to other plants that may be alternative hosts that could overwinter the pathogen. Doing this in association with crop rotation will help give time for the pathogens to die off. Typical crop rotations allow for 3-

A field that has been cleared of plant debris, run through with a disc and then planted with cover crops. F. Becker photo.

4 years between planting a crop in the same family.

Fruit Pests

Stink bugs are still active and can be found along wood-lines and field edges. Although, numbers do seem to be dropping as the summer comes to an end. I am still finding the occasional fruit that has been damaged by a stink bug. The damage is typically occurring in trees along the edges of orchard blocks, especially near wooded areas.

Wayne County IPM Notes from September 13-September 19

Vegetable Pests

Large masses of cucumber beetles on pumpkin plants late in the season. F. Becker photo.

Cucumber beetles continue to have high populations in pumpkin fields. The spotted cucumber beetle, which is also the southern corn rootworm adult, are migrating in masses out of corn fields as corn silks dry down and finding their way into pumpkin fields. So long as the beetles are not chewing on the skin of the pumpkin, they are not anything to be concerned about, however, if they start damaging the skin of the fall vine crops, an insecticide application may be warranted.

Scouting your latest plantings of cole crops is recommended to make sure that cabbageworms do not get out of hand. It can be easy to let your guard down as the season winds down, but if you want to have a marketable crop, you need to keep an eye out for the imported cabbageworms doing damage.

Vegetable Diseases

Peppers, at this point in the season should be winding down, however, disease pressure can force a premature end

Anthracnose lesions on a bell pepper. F. Becker photo.

to the season quite rapidly. One disease that can cause a rapid decline in peppers is anthracnose. At this point in the season, it is not worth the investment in any fungicide applications. For future planning, practice a three-year crop rotation with crops that are not in the Solanaceae family and consider doing seed disinfestation before planting. This disease can be managed with fungicides; however, it is important to address the issue of the origin of the diseases, rather than trying to fix the issue by applying a rescue fungicide every year.

At this point in the season, it is of your best interest to consider the cost of any fungicide application in respect to how much more you expect to get out of a crop. With pumpkins, for example, as the plants are beginning to die off at this point in the season, it is not likely that any fungicide application will be effective or result in any increase of yield or crop value. For a crop like cole crops that are just a few weeks in the ground, then you may have opportunity to apply fungicides, should the need arise. As always, follow the label and pay close attention to the pre-harvest interval when applying a fungicide.

Fruit Pests

Stink bugs are still active and can be found along wood-lines and field edges. I am still finding the occasional fruit that has been damaged by a stink bug. The damage is typically occurring in trees along the edges of orchard blocks, especially near wooded areas.

Fruit Diseases

Apples are now ripening and being harvested in orchards around Wayne County. F. Becker photo.

As fruit continues to ripen and be harvested, we continue to move forward through the growing season without many disease issues in our area. If you are doing any final treatments for fruit diseases, pay close attention to the PHI on the product label. The pre-harvest interval determines how long after you applied that product that you may harvest the crop. This is especially important to pay attention to as many varieties of orchard crops as well as grapes are maturing and nearing harvest.

Wayne County IPM Notes from August 30 – September 5

Vegetable Pests

Various sizes of stink bug nymphs in the leaf litter of fall vine crops. F. Becker photo.

With daytime high temperatures becoming cooler, we are starting to see more and more activity from the squash bugs. If you are actively harvesting your fall vine crops, the squash bugs may not be of concern to you. However, if you are not yet harvesting or choosing to leave your fall vine crops out in the field, the squash bugs can and will do damage to the skin of the pumpkins and gourds. The best time to scout your fields to look for squash bugs is early in the morning or into the evening when they are not in direct sunlight. More on squash bug management.

Cucumber beetles have made a late season come back, much to the dismay of many fall vine crop growers. The cucumber beetles, this late in the season, tend to do very little damage to the foliage of the plants. What they do go for is the fruit instead. Beetles will damage the skins of pumpkins and gourds. This leaves the pumpkins and gourds as less desirable crops and also opens them up to infection and secondary insect pests that would otherwise not affect the fruit.

Late season damage being done by cucumber beetles. F. Becker photo.

Stink bugs are out and doing damage to crops such as tomatoes. The stink bugs activity and feeding starts to increase most noticeably from late July through August and they remain active through the end of the growing season. Their damage on green tomatoes may appear as small, whiteish areas. On ripe tomatoes, the damage shows up as a golden yellow “starburst” pattern. While this damage is typically only cosmetic, higher amounts of feeding can result in infection and result in the fruit being unmarketable.

Vegetable Diseases

Plectosporium blight on pumpkin can cause significant crop losses. The disease typically presents itself as diamond shaped lesions on the stems and can also affect the veins on the leaves, although it can infect all parts of the plant. The lesions start out small but can quickly cover the entire stem. This disease has started to show up within the last few weeks in Ohio due to the favorable conditions of rain, and cooler temperatures.

Plectosporium blight lesions on a pumpkin stem. F. Becker photo.

A common thing to see in pumpkin fields as plants are maturing is yellowing leaves and the leaves starting to die back. Although there may be diseases such as powdery mildew present in the field, this rapid deterioration is not likely solely the result of the disease pressure and rather the natural senescence of the plant. As the plant matures and the pumpkins and gourds begin to cure, the plant has essentially reached the end of its life cycle. The leaves begin to change from dark green to a pale green/yellowish color and will eventually begin to die back. So long as this is happening at the end of the season and the pumpkins and gourds are mature, there should be no concern.

Fruit Pests

Spotted wing drosophila have been active in small fruits for some time, but with peaches now being harvested, the SWD can and will target the peaches as well. I have found peaches that have SWD larva feeding just under the skin. SWD can also do damage to grapes. I have started to find berries in grape clusters that were soft or looked poorly. Just under the skin of these grapes I found SWD larva feeding and moving around. Many grapes are ripening and getting close to harvest so anyone with grapes should consider treating for SWD.

Stink bugs can also do a lot of damage to fruit crops this time of year. I have set out traps and they are already showing very active stink bug populations. I am also finding damage from stink bugs in orchard crops. Most of the damage I am finding has been occurring in apples. This damage appears as a discolored depression in the skin with corking of the flesh all the way up to the skin. This damage can occur anywhere on the apple, although it can be frequently found on the “shoulder” of the fruit.

Fruit Diseases

Overall, disease pressure has been fairly limited this year. Hot and dry conditions have prevented favorable conditions needed for disease development. As fruit continues to ripen and be harvested, we continue to move forward through the growing season without many disease issues in our area. If you are doing any final treatments for fruit diseases, pay close attention to the PHI on the product label. The pre-harvest interval determines how long after you applied that product that you may harvest the crop. This is especially important to pay attention to as many varieties of orchard crops as well as grapes are maturing and nearing harvest.

Apple that has cracked and split after a heavy rain following drought conditions. F. Becker photo.

After this recent round of heavy rain and subsequent heat and high humidity, apple growers should be aware that some apples may crack or split while still on the tree. We are fortunate that we were beginning to have some more frequent rains that were starting to alleviate drought conditions, and this prevented rapid uptake from the trees. Typically, when a heavy rain occurs after prolonged dry spells or during drought conditions, there is large amounts of moisture taken up through the roots as well as absorbed through the skin of the fruit. This results in rapid cell expansion and thus cracking, and splitting occurs.

Wayne County IPM Notes from August 16 – August 22

Vegetable Pests

Stink bugs have started to feed on and damage crops such as tomatoes. The stink bugs activity and feeding starts to increase most noticeably from late July through August and they remain active through the end of the growing season. Their damage on green tomatoes may appear as small, whitish areas. On ripe tomatoes, the damage shows up as a golden yellow “starburst” pattern. While this damage is typically only cosmetic, higher amounts of feeding can result in infection and result in the fruit being unmarketable.

Flea beetles feeding on young, fall planted, cole crops. F. Becker photo

Flea beetles continue to feed on several crops including tomatoes and cole crops. The feeding on tomato plants is not of major concern mostly because the damage I am seeing is on the lower leaves. The damage on cole crops is of more concern due to the areas of the plants being damaged. The flea beetles are feeding on young tender leaves on kale plants as well as causing heavy damage on young plantings of broccoli and cabbage. Too much damage at this point can stunt the plants growth and result in reduced yield.

The trap counts for sweet corn pests in Wayne County are overall down. Sweet corn growers should be keeping an eye out for army worm damage as we have had reports of high fall army worm trap counts as well as damage that was being done by the yellow striped army worm. More on recent trap counts

Vegetable Diseases

            Downy Mildew is in Wayne and Medina counties and likely in surrounding counties as well. Cucumber growers need to be spraying for downy mildew.

Powdery mildew can be just as destructive on squash as downy mildew is on cucumbers. I have been finding powdery mildew consistently in younger squash plantings. Unfortunately, the earlier the plant is infected with powdery mildew, the shorter the life span of the plant. With an infected plant having a short life span, the yield for the plant can also be expected to decrease.

Smut is especially prevalent on sweet corn this year. Smut is more common during hot and dry weather, especially when followed by a heavy, warm rain. This year has been the perfect year for prime smut infection and growth.

In some pepper fields, there has been a few spots of anthracnose found on the fruit. Anthracnose typically does not affect the pepper foliage; however, the pepper fruits are highly susceptible to infection from the disease. Peppers develop large sunken lesions with pink to orange colored spores. This disease can be found typically on the lower sets of fruit, where they are more likely to be splashed with soil from heavy rains.

Fruit Pests

Spotted wing drosophila have been active in small fruits for some time, but with peaches starting to ripen, the SWD can and will target the peaches as well. I have started to find peaches that have SWD larva feeding just under the skin.

SWD can also do damage to grapes. This week I started to find berries in grape clusters that were soft or looked poorly. Just under the skin of these grapes I found SWD larva feeding and moving around. Many grapes are ripening and getting close to harvest so anyone with grapes should consider treating for SWD.

Brown marmorated stink bug trap with adults and nymphs present. F. Becker photo.

Stink bugs can also do a lot of damage to fruit crops this time of year. We have traps out for the brown marmorated stink bug, which will help us monitor its population, however, I am already finding some stink bug damage on peaches and apples. This damage appears as a discolored depression in the skin with corking of the flesh all the way up to the skin. This damage can occur anywhere on the apple.

Fruit Diseases

            Overall, disease pressure has been fairly limited this year. Hot and dry conditions have prevented favorable conditions needed for disease development. As fruit continues to ripen and be harvested, we continue to move forward through the growing season without many disease issues in our area.

Some grape varieties are nearing harvest. At this point, there should be no significant disease concerns, especially so close to harvest. The same goes for orchard crops.

If you are doing any final treatments for fruit diseases, pay close attention to the PHI on the product label. The pre-harvest interval determines how long after you applied that product that you may harvest the crop. This is especially important to pay attention to as many varieties of orchard crops as well as grapes are maturing and nearing harvest.

Optimizing Plant Spacing (Population) and Seasonal Nitrogen Rates in Grafted Watermelon Production

Data collection on fruit taken from two “grafted watermelon” experiments being completed at the OARDC in Wooster,OH has started. These experiments were outlined in VegNet posts on June 6 and July 11 and they are described in the image below, too.

Harvest 1 occurred on 8/19/20 with ‘Jade Star’ fruit harvest and analysis. The first harvest of ‘Fascination’ will be the week of 8/24 and a second harvest of each variety from both experiments is also planned. We assess the maturity of each fruit and its readiness for harvest using these criteria: a) yellow belly, b) dry vine tendril, c) developing longitudinal ridges, and d) white stripes brightening and widening (‘Fascination’). Occasionally, fruit weighing less than 8 lb meet one or more of these criteria, so they are harvested and photographed along with all other fruit from the same plot. Fruit weighing less than 8 lb are later separated from the group of fruit weighing more than 8 lb (marketable). In all pictures below, fruit are shown on a blue tarp slightly larger than 7 ft wide x 4 ft tall.

Pictures below are representative of what was observed in replicates 1-3 but conclusions should not be drawn from them. Data from Harvest 2 are needed to complete the picture and all data from 2020 must be analyzed along with data from previous years of the research (2018, 2019). On 8/19/20, in the “density” study, we observed that all four plots containing grafted plants produced a total of 12 fewer fruit than the four plots containing grafted plants at an in-row plant spacing of four feet. However, the situation was reversed at an in-row plant spacing of five feet since the four plots containing grafted plants produced a total of thirty-five more fruit than the four plots containing ungrafted plants at the same spacing.

The last planned fertilizer application (fertigation) in the “fertility” study was completed on 8/21/20. Two days before, the number of fruit taken from all twelve plots containing grafted plants was greater than the number of fruit taken from the twelve plots with ungrafted plants, regardless of seasonal nitrogen (N) rate. The difference in fruit number was greatest, moderate, and least at 75%, 100%, and 50% of the normal N rate, respectively. The pictures below are an example of the difference in fruit number at the standard N rate developed for watermelon production using ungrafted plants.

The experiments are being completed with USDA-SCRI program support and we look forward to sharing the results when the work is complete. In the meantime, please contact us (kleinhenz.1@osu.edu; 330.263.3810) for more information.

Wayne County IPM Notes for August 9 – August 15

Wayne County IPM Notes

Vegetable Pests

Aphids feeding on the under side of a pumpkin leaf. F. Becker photo.

In many crops, I am starting to see aphids feeding on the underside of the leaves. Most consistently, I have seen this in pumpkins. The aphids cause direct damage to the leaves via their feeding, but they can also cause other issues such as the sooty mold that happens as a result of their exudate known as honeydew. Additionally, aphids can potentially transmit viruses from plant to plant.

Flea beetles are still a problem in both young, recently transplanted crucifer crops, as well as cabbage and kale either in harvest or near harvest. Feeding damage from flea beetles on the younger crops can cause stunting and reduced yield. This damage can be especially impactful on heat stressed transplants. The foliar feeding being done on maturing crops can affect the visual appearance of the crop and may result in a less desirable product.

In cucurbit crops, the main pests causing problems are cucumber beetles and squash bugs. The cucumber beetle and their larvae can be found causing damage to both pumpkin and melon skins throughout the fields. Squash bug eggs are starting to hatch, and I am starting to find various stages of nymphs out in pumpkin fields and squash plantings. Currently most feeding is being done on the leaves; however, the focus of the feeding can shift to the fruit and cause scarring to the skin resulting in decreased marketability. The squash bug has also been found to be the vector of a bacterium that causes the disease Yellow Vine Decline.

Vegetable Diseases

            Downy Mildew is in Wayne and Medina counties and likely in surrounding counties as well. Cucumber growers need to be spraying for downy mildew.

Sweet corn ear with large smut galls. F. Becker photo.

As tomato plants put on more foliage, the airflow between plants is restricted, which results in higher moisture environments within the plants. This high moisture environment is conducive for several fungal infections such as Septoria leaf spot and early blight. Both of these diseases are currently becoming more prevalent in field tomato plantings. This is also happening after a few heavy rains where soil was splashed onto the lower leaves.

Powdery mildew can be just as destructive on squash as downy mildew is on cucumbers. I have been finding powdery mildew consistently in younger squash plantings. Unfortunately, the earlier the plant is infected with powdery mildew, the shorter the life span of the plant. With an infected plant having a short life span, the yield for the plant can also be expected to decrease.

Sweet corn growers have been finding a lot of smut on the ears and sweet corn plants. Smut is more common during hot and dry weather, especially when followed by a heavy, warm rain. This year has been the perfect year for prime smut infection and growth.

Fruit Pests

Japanese beetles are still feeding in nearly every crop that I am scouting. They are doing damage to apple leaves, peach leaves, grape leaves, blueberry leaves and blueberry fruit. It is important to watch the populations of Japanese beetles because they can transition from only feeding on the leaves to doing significant damage to the fruit.

In orchards I am seeing an increase in spider mite populations. This includes two spotted spider mites and European red mites. These mites, while not causing major damage initially, can cause significant damage over prolonged periods of feeding.

Spotted wing drosophila have been active in small fruits for some time, but with peaches starting to ripen, the SWD can and will target the peaches as well. I found a handful of ripe peaches this week with soft spots on them. Upon peeling the skin back, I could clearly see several SWD larva feeding in the peach.

There was a short time of limited codling moth and oriental fruit moth activity, however, the traps again picked up high counts of both moths this week.

Fruit Diseases

            Overall, disease pressure has been fairly limited this year. Hot and dry conditions have prevented favorable conditions needed for disease development. As fruit continues to ripen and be

Some grape varieties are nearing harvest. F. Becker photo.

harvested, we continue to move forward through the growing season without many disease issues in our area.

Apple and peach growers should continue their spray programs to manage fruit rots and diseases such as flyspeck and sooty blotch in apples and brown rot in peaches. Alternaria leaf blotch can be found on some apple trees right now. This can be made worse by red mite infestations. With high populations of mites and the leaf blotch, severe defoliation can occur.

Grapes should be starting to get some color to them as the clusters are starting to increase in size. Although symptoms of black rot may be showing up on untreated grapes, it is too late to do anything.  Growers with varieties of grapes that are not resistant to downy mildew should consider a spray program. Grape growers should also keep an eye out for powdery mildew, as this is the time of year when powdery mildew is typically found on grapes.