Editor – Frank Becker, Agriculture and Natural Resources Educator, Wayne County. Contributions made from team members around the state of Ohio.
General Update
Pest and disease pressure continues to be a concern, particularly with increased weed pressure this year as well as issues stemming from herbicide drift. While herbicide damage can cause cosmetic damage to perennial crops like fruit trees, it’s important to note that these do not always translate into yield penalties. In areas like orchards and vineyards, patience is key as plants recover from such damage. Please keep in mind that in order for the Department of Agriculture to adequately analyze plant material for herbicide drift, reports to ODA need to be made within 7-1o days of the drift event, and the sooner the better.
Fruit Update
Reports are coming in from several areas about Marssonina leaf blotch affecting apples. This fungal disease thrives in wet conditions and can lead to premature defoliation, weakening the tree. Regular fungicide applications and proper sanitation of fallen leaves can help manage this disease.
Several reports have come in of observed significant loss of raspberry and blackberry plants suspected to be caused by Phytophthora root rot. This is particularly troublesome in raised beds or container plants, where rotation can be difficult to implement. Phytophthora thrives in wet, poorly drained soils, and the disease can rapidly progress if not controlled. It’s important to use resistant cultivars, improve drainage, and avoid overwatering. If you suspect root rot, be sure to send in samples to the Plant and Pest Diagnostic Clinic for a more accurate diagnosis.
Insect activity has been relatively low across most fruit crops, though there have been sporadic reports of spider mites, spotted wing drosophila and third-generation oriental fruit moths (OFM).
Vegetable Update
Cucurbit fields are seeing multiple challenges, including bacterial wilt, which is becoming more widespread. Although the symptoms are visible now, the plants would have been infected with bacterial wilt some time ago via cucumber beetle feeding. This disease is vectored by the cucumber beetle and can cause wilting and death of the plant. In addition, angular leaf spot has been reported, which is a foliar bacterial disease. Plectosporium has also been observed, primarily in fall vine crop fields. Plectosporium can cause lesions to form on the stems and handles, causing handle integrity issues in these crops. Lesions may also form on the fruit, directly impacting fruit quality and marketability.
Recent field collected samples have shown bacterial issues on dill, which could be a sign of improper plant spacing, moisture issues, or bacterial contamination. The leaves are exhibiting typical signs of bacterial infection, so reducing overhead irrigation and removing affected plants can help minimize spread.
In tomatoes, pressure continues to increase from Septoria leaf spot, early blight and bacterial spot. These diseases tend to show up during wet periods and cause significant defoliation, which can reduce yields. Applying fungicides and bactericides to affected crops and practicing good sanitation and crop rotation can reduce the chances of recurrence.
On the insect side, activity has been relatively light. Some growers have observed garden millipedes feeding on decaying plant material, particularly in areas affected by bacterial wilt. These are only secondary pests in these cases and no control is needed. Flea beetle numbers are sporadic, and both imported cabbage worms and diamondback moths are being seen, but with thorough scouting and timely management decisions, can be effectively controlled.
Onions still in the fields have been under attack from salt marsh caterpillars and thrips. Both pests can cause significant damage, with thrips often being the primary concern due to their ability to spread viruses and cause leaf damage. Regular scouting is critical for managing these pests.
A few growers have reported broad mite issues in certain fields. Broad mites are particularly damaging in high humidity conditions and can cause distorted leaf growth. With the high weed pressure this year, it’s important to monitor how these pests may persist in weed refuges, potentially leading to future problems in subsequent seasons. When selecting miticides, ensure that you are reading the label to confirm that the products are listed for control of broad mites. Products listed for control of only red mites or two-spotted spider mites will not control broad mites.