Honey-colored mushrooms that seem to sprout out of nowhere. Weird lumps on roots or stems. Growths that look like witches’ brooms come to life.
That’s what keeps Baldo Villegas up at night.
“Those are the worst garden nightmares,” said Villegas, a retired state entomologist and Sacramento’s well-known “Bug Man.” “They’re the worst things a garden can get because there’s no practical treatment.”
Mushrooms, lumps and witches’ brooms are indicative of major plant diseases that can be disastrous for gardeners. Watching for signs of those diseases keeps Villegas vigilant. When let loose in landscapes, the diseases can lead to catastrophic consequences, he warned.
“Literally, you have to move,” he said of oakroot fungus, the source of those honey mushrooms that cause plants to slowly die from the bottom up. “There’s no practical solution. You don’t have to have oak trees to get this fungus in your garden; any woody ornamental is a potential host.”
This spring, Villegas has been spreading caution along with mulch. Villegas, who grows more than 3,000 rose bushes at his Orangevale home, has been busy offering his advice to local garden clubs as well as holding free clinics at nurseries.
Prevention is key, he stressed, because often there’s no easy cure.
Take, for example, bacterial crown gall, a contagious plant disease that attacks many ornamental plants. Recently, the disease has been found in new rose bushes and other shrubs grown by major wholesale nurseries, Villegas said. Galls or misshapen lumps form where the bacteria has entered the plant, usually through cuts or minor wounds near the plant’s crown or base. A little nick from a weed whacker can create an entry point.
The bacteria that causes the galls is common in agricultural soils, such as those found throughout the Sacramento Valley. That makes it difficult to keep out of home gardens, Villegas noted. Like tumors, the galls choke the plant of nutrients and water, stunt its growth and can kill the plant.
“Once this stuff gets in your soil, it’s there forever,” he said. “That’s why I demand clean (nursery) stock.”
Villegas cares for his 2-acre garden with integrated pest management, the same techniques he perfected while working with the state.
“I haven’t sprayed my garden in five years,” he said.
Instead, he tries to let nature take its course as much as possible with the help of beneficial insects and thoughtful gardening.
Spraying herbicides, most notably Roundup or glyphosate weed killer, can cause toxic reactions in nearby sensitive plants, such as roses, sycamores, maples, privets and many other ornamental shrubs and trees. The damage to those desirable plants can be irreversible.
Damage from herbicide exposure in roses can look a lot like rose rosette disease (RRD) or witches’ broom. Caused by a virus spread by a microscopic mite, real RRD is rarely seen in Central Valley gardens.
“When people self-diagnose RRD, it’s almost always Roundup damage,” Villegas said. “You can tell the difference by looking for the mites.”
Villegas personally researched RRD for many years. He’s found it in wild roses along Highway 395 in Mono, Nevada, Sierra, Lassen and Modoc counties.
“That’s all east of the Sierra,” he said. “Just don’t bring home any wild roses from that area.”
Before he adds any plant permanently to his garden, Villegas puts it in quarantine. For example, he pots up a new bare-root rose in a 5-gallon container and lets it grow a season in an area away from his other roses.
“I let it bloom,” he said. “I let it leaf out. I evaluate it, then decide if I really want to add it to my garden. This is so important, especially these days with so many Internet purchases. You need to make sure you aren’t introducing problems into your garden.”
If he finds problems, he notifies the nursery where he bought the plant. “They need to know,” he said.
Some issues can be spotted right away – at least on bare roots. Look out for lumps; they could be nematodes – microscopic roundworms that make knots in roots. While some nematodes are beneficial, others are not.
“Always look at the roots,” he said. “If there are any lumps, quarantine that plant and call an expert.”
If you’re experiencing a garden nightmare, Villegas recommends contacting the California Department of Food and Agriculture lab and diagnostics center in Sacramento and taking them a sample for free diagnosis. The center is located at 3294 Meadowview Road, Sacramento; call 916-262-1100 for details or an appointment.
Villegas’ advice: The best way to create your dream garden is to avoid nightmares as much as possible.