Wayne County IPM Notes
(From the Week of June 8 – June 12)
Frank Becker, OSU Extension Wayne County
The Colorado Potato Beetle is still feeding heavily, especially on potato. The larvae are out in large numbers and many egg clusters are hatching or will soon be. They are most effectively controlled in the larval stage. It is best to coordinate insecticide applications in line with when the egg masses are hatching, and young larva are starting to feed on the foliage.
Flea Beetles are still prevalent and doing damage. Flea Beetles will also utilize weeds as host plants. Keeping your fields free from weeds will help to reduce the populations of flea beetles.
Cucumber Beetles are out in force right now. For growers who use a seed treatment on cucurbit crops, keep in mind that the treatment is typically effective up to the 2-leaf stage, at which point the efficacy starts to decline. Cucumber Beetles vector the Bacterial Wilt disease so early season control of the beetles is vital to the long-term health of the plant.
In sweet corn, cut worm damage has started popping up along with some more significant European corn borer damage.
Onions are at a point where thrips populations could begin to increase. Consistent rains and small plants had kept the thrips population down, but with some drier weather in the forecast and onions increasing in size and putting on more leaves, this will be a pest to keep an eye on.
The Imported Cabbageworm larvae, among other worm pests of brassicas, are feeding on cole crops and leafy greens such as kale. Severe foliar feeding could stunt the plant growth or significantly reduce yield.
Timber rot of tomato is being found, especially in high tunnel tomatoes. This disease will take down a plant very rapidly. The survival structure, called a sclerotia, can survive in the soil for several years. It is important to allow for good airflow to avoid excess moisture in the tunnel. Additionally, it is recommended that if you are pruning to sanitize the tools between each cut. Diseased plants may also be removed and disposed of to prevent further spread of the pathogen. Find more details about timber rot and management options in this article by Sally Miller: https://u.osu.edu/miller.769/2016/06/22/white-moldtimber-rot-management-in-tomato-high-tunnels/
Botrytis is still being seen, as is blossom end rot. To manage blossom end rot, it is important to limit moisture stress on a plant, from either too much or not enough moisture. Being consistent in watering and monitoring soil moisture conditions will help to prevent exposing the plant to moisture stress. Proper moisture will also provide conducive conditions for adequate nutrient uptake, given that the nutrients are present at appropriate levels in the soil.
Strawberry producers typically are facing several insect pests this time of year. One of these pests is the eastern flower thrips. This small insect feeds on and damages the strawberry blossom. As the berry begins to develop, this damage results in cat-facing on the berry or a russeting/bronzed appearance. When you notice these symptoms on the developing berry, the damage has already been done and there are no treatment options. To look for thrips in the blossoms, take a white piece of paper or a plate and shake the blossoms onto the plate and watch for any small, slender yellow thrips to be moving around. Once you have reached 2 or more thrips per blossom, you should move forward with a treatment. Consider the pollinators before applying an insecticide, considering the target of your application is primarily associated with the blossoms. Preventative sprays can also be used in successive plantings. See more on Thrips in this post by Celeste Welty: Beware of thrips on strawberries
Another pest of strawberries and small fruits is the spotted wing Drosophila. The SWD is a small fruit fly that can lay its eggs in ripening fruit while it is still on the plant. As you are picking, do not discard unwanted fruit on the ground right next to the plant. The rotting fruit on the ground will attract SWD. Instead bring a bucket to discard unwanted fruit in and either bury it a foot or so deep in soil or seal the fruit in a clear plastic bag exposed to the sun for about a week to kill any larvae. If culls are discarded in the trash or compost pile, they might attract SWD flies and allow for more generations to be produced. This is also the time to put traps out in your bramble and blueberry patch but if you have June bearing strawberries, they likely won’t be affected by this pest. More details about how to set up traps can be in the OSU IPM YouTube page under the SWD playlist at https://www.youtube.com/channel/UCzcWaLH3mx7HUKh4OF7bYPA and on Celeste Welty’s page here: https://u.osu.edu/pestmanagement/
Codling Moth and Oriental Fruit Moth traps are showing low numbers right now.
Now is the time to be managing early season diseases in apples. Scab, rust and powdery mildew are the three main diseases of concern at this point in the season. It may also be appropriate to consider looking at managing summer diseases such as flyspeck, sooty blotch, and fruit rots.
Strawberry leaf diseases may appear unsightly right now, however, now is not the time to be managing these leaf diseases. Once harvest is done and during patch renovation it is recommended that you address these concerns, either with a fungicide or with resistant plant varieties. This is also a critical time to be watching for fruit rots such as Botrytis.
Grapes are currently either at pre-bloom or blooming. This stage is the most critical stage of development for controlling diseases. Fungicide applications for black rot, powdery mildew and downy mildew are highly recommended during this time. See more details about grape black rot here.