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Weather, Pests Make Summer Squash One Of The Most Difficult Vegetables For Home Gardeners To Grow

By Sharon Dowdy
 
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A yellow squash matures on the vine of a squash plant growing in Butts County, 
 
Pests and diseases make summer squash one of the most challenging vegetables to grow in Georgia home gardens, according to University of Georgia plant pathologist Elizabeth Little, who studies plant diseases and control methods at the UGA College of Agricultural and Environmental Sciences.
 
“Through my plant pathology experience and observations, I’ve noticed what is most difficult to grow in Georgia’s hot, muggy summers. Squash tops the list,” Little said. “That’s why summer squash will grow better where summer conditions are cooler and drier.”
 
Insects like squash vine borers and squash bugs often dine on summer squash.
 
Squash vine borer moths lay eggs at the base of the squash plant and the larvae feed within the stem. Their feeding damages the plant, causing it to wilt and collapse. The only sign of the pest is sawdust-like frass at the base of the stem. 
 
There is no guaranteed way to control squash vine borers aside from planting a resistant variety of squash. UGA Cooperative Extension horticulturist Bob Westerfield tells backyard gardeners to plant extra squash plants, “some for you and some for the squash vine borers.”
 
In May, squash bugs lay eggs in the first planting of summer squash and remain in the garden. They can carry a bacterial disease that causes the plants to wilt and die, Little said.
 
“Insects can be seen on plants, but diseases are a little mysterious,” she said. “You can’t just look at the plant and see the microscopic pathogens.”
 
Viruses often knock out summer squash plants during July and August. To fight viruses, Little suggests that home gardeners plant an early crop of squash, then wait until the fall and plant again. 
 
Many squash diseases strike plants by July and August. The key is to stay ahead of the diseases, Little said. Choose an open, sunny spot and plant early in the season. Keep plants healthy through good fertility and soil conditions, she said. 
 
“If you wait until after you see the disease, it’s too late,” she said. “It’s all about prevention. There is no cure.”
 
Downy mildew, a water mold, can also be a problem in summer squash, according to Little. The mold hurts the leaves of the plant, which affects photosynthesis.
 
Downy mildew doesn’t survive over the winter, but it moves from south Georgia each year and shows up in north Georgia by June or July, she said.
 
“It’s not an early-season disease, so planting early can help,” she said.
 
Powdery mildew loves Georgia’s hot, humid summers and summer squash. Some squash cultivars were bred with resistance to the disease.
 
To help cut down on disease pressure in the home garden, have a “squash-free period” during the height of summer. This helps stop the cycle of pests and disease, Little said.
 
Fruit can start to rot during wet weather. To fight fruit rot, improve air circulation in the garden by making sure plants are not crowded. Keep the fruit dry and off the ground by placing leaves or landscape cloth under the fruit. 
 
In general, Little recommends that backyard gardeners search for vegetable varieties that grow best in hot environments. 
 
Tomatoes and pumpkins are also on Little’s list of vegetables that are hard to grow in Georgia due to pests and diseases, but she says that watermelons and other melons grow well in Georgia heat.
 

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Why Your Food Future Could be Trapped in a Seed Morgue

Video: Why Your Food Future Could be Trapped in a Seed Morgue

In a world of PowerPoint overload, Rex Bernardo stands out. No bullet points. No charts. No jargon. Just stories and photographs. At this year’s National Association for Plant Breeding conference on the Big Island of Hawaii, he stood before a room of peers — all experts in the science of seeds — and did something radical: he showed them images. He told them stories. And he asked them to remember not what they saw, but how they felt.

Bernardo, recipient of the 2025 Lifetime Achievement Award, has spent his career searching for the genetic treasures tucked inside what plant breeders call exotic germplasm — ancient, often wild genetic lines that hold secrets to resilience, taste, and traits we've forgotten to value.

But Bernardo didn’t always think this way.

“I worked in private industry for nearly a decade,” he recalls. “I remember one breeder saying, ‘We’re making new hybrids, but they’re basically the same genetics.’ That stuck with me. Where is the new diversity going to come from?”

For Bernardo, part of the answer lies in the world’s gene banks — vast vaults of seed samples collected from every corner of the globe. Yet, he says, many of these vaults have quietly become “seed morgues.” “Something goes in, but it never comes out,” he explains. “We need to start treating these collections like living investments, not museums of dead potential.”

That potential — and the barriers to unlocking it — are deeply personal for Bernardo. He’s wrestled with international policies that prevent access to valuable lines (like North Korean corn) and with the slow, painstaking science of transferring useful traits from wild relatives into elite lines that farmers can actually grow. Sometimes it works. Sometimes it doesn’t. But he’s convinced that success starts not in the lab, but in the way we communicate.

“The fact sheet model isn’t cutting it anymore,” he says. “We hand out a paper about a new variety and think that’s enough. But stories? Plants you can see and touch? That’s what stays with people.”

Bernardo practices what he preaches. At the University of Minnesota, he helped launch a student-led breeding program that’s working to adapt leafy African vegetables for the Twin Cities’ African diaspora. The goal? Culturally relevant crops that mature in Minnesota’s shorter growing season — and can be regrown year after year.

“That’s real impact,” he says. “Helping people grow food that’s meaningful to them, not just what's commercially viable.”

He’s also brewed plant breeding into something more relatable — literally. Coffee and beer have become unexpected tools in his mission to make science accessible. His undergraduate course on coffee, for instance, connects the dots between genetics, geography, and culture. “Everyone drinks coffee,” he says. “It’s a conversation starter. It’s a gateway into plant science.”