Weekly Field Update
Clemson Extension agents provide updates in The South Carolina Grower this week about the status of various crops being produced throughout the state.
Tom Bilbo – Extension Vegetable Entomologist
- Check out the updated Strawberry IPM Guide, now available on the Southern Region Small Fruits Consortium website.
- If you are a brassica grower, please help us by taking this short survey regarding diamondback moth. Your participation is very helpful and valuable to our research!
- In the warmer parts of the state, we are seeing diamondback moth (DBM) numbers begining to increase. The good news is we are already seeing high rates of DBM parasitism by parasitoid wasps. These parasitoid wasps are very important factors in regulating DBM populations…as long as they aren’t killed by broad-spectrum insecticides. In an ongoing trial at the Coastal REC in Charleston we are already seeing >70% of DBM being parasitized and killed by these wasps. You can conserve these helpful wasps by waiting to spray until DBM reach an economic threshold and then using ‘IPM-compatible’ insecticides.
- For some growers and crops, the weekend provided some welcome rainfall of up to 2.12 inches. The precipitation will be welcome in the development of many crops. That being said, scouting for pests and diseases will remain paramount. The forecast indicates some windy conditions. While wind can be advantageous in drying crops, there is the potential for twisting and damage to plants.
- Strawberries in the area are looking good. However, removing any water-soaked berries will be paramount and allied to fungicide applications to help manage anthracnose and botrytis fruit rots. Spider mites are being observed in high numbers on farms at present in a range of crops.
- Brassicas are developing well, with great vigor. Disease levels remain low. However, crops must be monitored closely to manage any disease pressure following rainfall. Diamondback moths are active. Remember to rotate different modes of action of insecticides to prevent resistance. We can offer a bioassay to determine resistance to insecticides. Reach out to an agent, and we will be happy to help.
- Cucurbit crops are generally looking good. Keep scouting for cucumber beetles and squash bugs as both are currently being found in crops. Watermelon planting continues on many farms, with damage being observed to new transplants from squash bugs. Spider mites are also being seen at high levels in some watermelon crops.
- Feeding damage from spider mites typically appears as a yellow chlorotic mottling to the upper leaf surface. The insects feed on the leaf’s underside, and adults or eggs are likely to be found using a hand lens. If you do not have a hand lens available, a cell phone camera can be used to enhance the image by zooming in.
- Blueberries continue to come to harvest with great quality and volume.
- Things are moving along nicely along the coast.
- Strawberries are making another flush thanks to some cool nighttime temperatures.
- Spring greens, onions and herbs look great.
- A tomato grower told me that this has “been a boring tomato season so far, and that’s a good thing.”
- For some Midlands growers and crops, the weekend provided some welcome rainfall of up to 1.34 inches. The precipitation will be welcome in developing many brassicas, corn and other vegetables.
- Strawberries in the area are looking good. However, removing any water-soaked berries will be paramount and allied to fungicide applications to help manage anthracnose and botrytis fruit rots. Spider mites are being observed in high numbers on farms in various crops.
- Brassicas are developing well with great vigor. Levels of foliar disease remain low. However, crops must be monitored closely to manage disease pressure following rainfall. Diamondback moths are active; remember to rotate different modes of action of insecticides to prevent resistance. We can offer a bioassay to determine resistance to insecticides. Reach out to an agent, and we will be happy to help.
- Cucurbit crops are generally looking good. Keep scouting for cucumber beetles and squash bugs, and both are currently being found in crops.
- Strawberries seemed to be picking up a bit last week, and fruit started to ripen quicker. With the chilly night temps, we will likely see things slow down again this week. Keeping an eye out for spider mite flair ups. We’ve had some hot spots here and there.
- We have started harvesting peaches, mainly in the Santee area, but some are coming off around the Ridge as well. Fruit is a little on the small size right now. Some fruit is starting to show “cat clawing” as it sizes. This occurs, likely from the cold damage, when splitting or cuts/lesions appear on the skin as the fruit expands. Hopefully, quality will improve as we move into the season. We expected issues like this due to the freeze events, and our early varieties seemed to take the biggest hit.
- Parts of the Pee Dee have been experiencing rather heavy rains. This is causing higher-than-usual water tables and ponding water in some fields, delaying some plantings.
- Cool, cloudy conditions are causing some problems with bean and pea emergence (slow emergence and off-color).
- Sweet corn is looking good for the most part.
- Many growers are planting pepper, tomato, eggplant, watermelon and cantaloupe transplants now.
- Strawberries are looking good. Crown rot is still lingering around and causing plant loss. Root rot is starting to show up (rather widespread) too. Strawberry harvest is a bit off with most growers coming up short compared to normal years.
- Blueberries are starting to come into harvest. Fruit looks good, but be mindful of lingering cold injuries like frost rings and corky fruit.
- Muscadines are getting close to flowering. Monitor for flea beetles, aphids, and thrips activity, and treat if necessary.