What is in this article?:
- Old disease continues assault on Georgia melons
- Rotation not working
• Fusarium thrives in cool spring conditions, which persisted in much of Georgia’s watermelon growing region this spring.
• Though not labeled yet for melons, some fungicides used now for agronomic crops, like peanuts, can be used to control Fusarium in melons.
FUSARIUM WILT isn’t a new watermelon disease, but this old soilborne enemy is starting to take its toll on seedless watermelon production in Georgia, like this melon in early May. The disease so far is out zigging the zag of ways to control it.
Rotation not working
But something else is now happening. That rotation management doesn’t seem to be working as well as it once did. Langston has seen fields that have been out of melons for 10 years show signs of economic damage due to Fusaruim wilt. “So the rotational component of our control recommendations is being bypassed somehow by the pathogen, and we’re not real sure how that is happening,” he said.
Fusarium wilt, he said, is now the primary threat disease-wise to Georgia melons. Simply because there are no adequate control methods for it, especially considering that even the rotation management is now compromised.
Grafting watermelons to gourd rootstock, which isn’t hurt by the disease, is doable but very expensive and not widely practiced. And there are some fungicides used now for agronomic crops, like peanuts, that can be used preplant to effectively control Fusarium, he said, but none is labeled for watermelons. “Hopefully we’ll get something labeled for watermelons in the next couple of years.”
Controlling root-knot nematodes with a preplant fumigation can combat Fusaruim damage in melons “because root-knot nematode feeding predisposes watermelons plants to Fusarium wilt,” he said. “Some of the worst damage we see from this is in fields where we knew or could tell were infested with root-knot nematodes.”
Mother Nature can help. Fusarium is a cool season disease. When daytime temperatures reach mid-80s to low 90s for a few days, the disease shuts down. Unfortunately, most damage is done to young melons by this time in Georgia, especially this year when cool spring weather lasted well into May.
Watermelons are big business in Georgia, worth about $100 million annually. Georgia is usually second or third in production each year. Sometimes No. 1. Georgia farmers plant 25,000 to 30,000 acres of melons each year, shooting to sell them around the Fourth of July, the mother of all melon-consuming holidays. Right now, there should be plenty of Georgia melons available for the holiday. The crop, overall, looks good.