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.

Late Season Pumpkin Pest – Aphids

Jim Jasinski, Department of Extension; Celeste Welty, Department of Entomology

Aphids on lower leaf surface.

While most growers have focused on managing cucumber beetles and squash bugs to this point in the season, now it’s time to be vigilant for a common late season pest, aphids. While there can be several species of aphids that invade pumpkin and squash fields in mid to late summer, the melon aphid is likely most common. Regardless of the species in your field, aphid biology and management are similar.

More aphids on a leaf.

Like squash bugs, aphids have sucking mouth parts. Aphids feed on the underside of leaves where tremendously large populations can build up quickly even with natural enemies (ladybugs, green lacewing larvae, parasitoid wasps, syrphid fly larvae, etc.) in the field, especially under hot and dry conditions. A by-product of their feeding is called honeydew, and when high aphid

populations exist, this sticky liquid can drip onto foliage and fruit creating a perfect condition for black sooty mold to grow on the surface of fruit which will need to be washed off prior to sale.

While aphids can create the environment for sooty mold, they can actively vector viruses to pumpkin and squash plants. A survey conducted in the late 1990’s by OSU researchers concluded that Watermelon Mosaic Virus was the most common type of virus found in Ohio pumpkin fields. Viruses in general may not be a serious threat to older plants where the fruit mature, but for younger plants with immature and developing fruit, distorted and strappy leaves, bumpy mosaic colored fruit or no fruit may result. While it is possible to treat pumpkin and squash plants for aphids, if an aphid feeds on a plant for just a second and then picks up a lethal dose of insecticide, the virus may already be vectored to that plant.  As a practical matter, virus transmission cannot be stopped using insecticides alone. Timing of planting is perhaps more effective, with earlier planting leading to potentially less virus incidence because fewer aphids are present as the crop matures.

Pumpkin leaves infected with virus.

Fruit infected with virus.

Sooty mold on pumpkin rind.

Sooty mold on foliage.

If scouting reveals aphid populations building in a field, even in the presence of natural enemies, treatment may be warranted if honeydew and black sooty mold are seen. While pyrethroids are relatively inexpensive to apply, they are devastating against most natural enemies and will likely cause an even more severe outbreak of aphids soon after application. The following products are non-pyrethroid alternatives, and their relative price compared to pyrethroids ($) are listed. Recent systemic materials such as Beleaf ($$$) and Fulfill ($$$) target sucking pests and should be less disruptive to natural enemies.  Other products such as Assail ($$), Sivanto ($$$), Harvanta ($$$$), and Exirel ($$$$$) are also likely to have high efficacy and less disruptive to non-target pests. A full list of recommended insecticides and their PHI’s can be found in the Midwest Vegetable Growers Guide (https://mwveguide.org).  

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.

Do you recognize stink bug injury on sweet corn?

As the brown marmorated stink bug (BMSB) becomes more well established around Ohio, its injury on sweet corn is becoming noticeable. In plantings that are sprayed frequently with pyrethroids such as Warrior or Hero for control of corn earworm, injury by stink bug is less likely to occur because pyrethroids are among the few insecticides that are toxic to stink bugs. But in plantings of transgenic sweet corn that do not need to be sprayed with insecticide for worm control, or in sweet corn that is sprayed by Coragen or Radiant for worm control, injury by stink bug is more likely to occur. Stink bugs feed by sucking juices from the kernels, after inserting their mouthparts through the husks (Figure 1). This results in kernels that are shrunken in a variety of ways, as shown in Figures 2 and 3 below. Both the adults (Figure 4) and the immature nymphs (Figure 5) feed on the kernels. The injury can occur anywhere on the ear; sometimes it is clustered near the tip, other times it is scattered along the entire length of the ear. In addition to sweet corn, BMSB has a wide range of host plants, ranging from raspberries, peaches, apples, and grapes to bell peppers, eggplant, green beans, swiss chard, and tomatoes.

-Celeste Welty, Extension Entomologist

Figure 1. Sweet corn ear being fed upon by adults and nymphs of the brown marmorated stink bug.

 

Figure 2. Sweet corn ear with many kernels injured by stink bug feeding.

 

Figure 3. Close-up view of kernels damaged by stink bug.

 

Figure 4. Adult of the brown marmorated stink bug.

 

Figure 5. Nymph of the brown marmorated stink bug.

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.

Update on worms in sweet corn and peppers

Last Saturday, I wrote that the corn earworm population was lower than usual for this time of year, but then two days later, last Monday, our traps in Columbus had the highest catch of the year. Populations of corn earworm are still moderate in size, not yet in the high range, but sweet corn fields that are silking will be at risk of infestation if control measures are not taken. As the local large acreage of field corn begins to dry down, the relatively small fields of sweet corn will be more attractive to the increasingly larger number of moths in the area. Sweet corn and pepper growers who have their own traps are encouraged to check the traps several times per week. Growers who do not have their own traps should check our website where trap reports are published.

Trap reports for corn earworm and European corn borer from several Ohio locations can be found using this link: https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=0

More information about trap-based insecticide spray scheduling for sweet corn is available using this link: http://u.osu.edu/pestmanagement/crops/swcorn/ .

-Celeste Welty, Extension Entomologist

 

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.

Worms in sweet corn and peppers

Almost every year at this time, we see a surge in activity of corn earworm, mostly from large numbers of corn earworm moths that blow up on weather fronts from the southern USA. This year has been unusual so far, in that we are seeing only a slight increase in corn earworm moths, and not yet seeing a large surge. This could change at any point, but it means that for now, growers should be able to get good control of worms in silking corn using insecticide at a less intense schedule than usual for August. At our Ohio sites that reported trap catch this past week, there were 0 to 9 moths in the Scentry type of pheromone trap. The recommended spray interval during hot weather (high >80 F) is every 4 days when traps are catching 3.5 to 7 moths per week, or every 3 days when traps are catching 7 to 91 moths per week, as shown in the table below.

   Spray schedule for silking sweet corn.

More information about trap-based spray schedules is available using this link: http://u.osu.edu/pestmanagement/crops/swcorn/ .

We have observed in our Ohio insecticide trials that in years when corn earworm moths are abundant, pyrethroid insecticides such as Warrior, Brigade, Mustang Maxx, Baythroid, and permethrin do not provide very good control even when used at the maximum labelled rate, however in years when corn earworm moths are not very abundant, pyrethroids can provide very good control, if used at the maximum labelled rate.

The other worm pest that is very important during August of most years is the European corn borer. Although this pest has been less abundant during the past 10-15 years than previously, throughout the Midwest, it still can be a key pest of peppers and sweet corn in late summer. We usually see its first generation larvae in June, and its second generation larvae in August. We expect to see larvae once we see the adult moths present, as can be detected by pheromone traps and blacklight traps. The first moths are usually found in traps in the last week of July. However, this year, we are seeing very few moths through mid-August. They are still likely to appear, but they are running a few weeks later than usual.

Trap reports for corn earworm and European corn borer from several Ohio locations can be found using this link:  https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=0

-Celeste Welty, Extension Entomologist

Wayne County IPM Notes for August 2 – August 8

Wayne County IPM Notes

Vegetable Pests

Yellow-striped army worm that was found down in the whorl of a V8 corn plant. F. Becker photo.

Army worms have continued to do damage to sweet corn plants. The damage I am finding is typically being done in the whorls on the young tender leaves. Another sign of army worm feeding is large areas along the leaf edges that have a ragged appearance.

Flea beetles continue to be 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 the larva can be found causing damage to melon skins throughout the fields. Squash bug eggs are starting to hatch, and I am starting to find various stages of larva 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

Early blight on a tomato leaf. 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.

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.

Fruit Pests

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.

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.

After a few weeks of high numbers in both oriental fruit moth and codling moth traps, the trap counts have started to back down a bit.

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.

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. “Managing Grape Diseases” 

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.