Pests rely on our inattention. If they're out of sight, they're out of mind. During winter months, beetles, borers and their brethren burrow deep in our gardens, waiting for warmth and opportunity. Likewise, voles and other crafty critters seek their openings to invade our space.
"Many people think there's nothing out there in wintertime," said El Dorado County Master Gardener Phyllis Lee. "They don't see it but it's still there."
Instead of making pests' lives harder, we humans actually help them out. In particular, we unwittingly give bugs and plant diseases a lift, moving them to new areas to conquer.
At stake is more than backyard fruit trees or favorite plants California agriculture also is at risk.
Just like homeland security, vigilance is key to stopping these threats. The more eyes, the better.
That's why agricultural experts seek backyard gardeners' help in stopping potential infestations. Our backyards may be the first line of defense against such potentially devastating pests as Japanese beetles and the Asian citrus psyllid.
"(The psyllid) is bound to get here," said Chuck Ingels, UC Cooperative Extension farm adviser for Sacramento County. "We need to keep an eye out. It's a real threat to all of our citrus trees everywhere."
Often, pests' favorite mode of transportation is firewood. Old logs can carry all sorts of pests. And winter is when people tend to move wood.
Or these pests may hitch rides in potted plants, grafted wood, sod or soil. However they got here, they likely had human help.
At California's borders, agriculture inspectors are on the lookout for destructive pests such as the emerald ash borer or the Asian longhorn beetle.
How common are these bad bugs? Recently, inspectors found in a load of firewood a 6-foot log that contained more than 10,000 destructive beetles.
Another unwanted traveler: fire ants. Common in Texas and Southern states, these aggressive ants often hide in firewood.
"These pests would be perfectly happy in California," said Leigh Greenwood, manager of the Nature Conservancy's "Don't Move Firewood" campaign. "They could be out there already, but we just don't know it yet."
The campaign recommends keeping firewood within 50 miles of where it was harvested; closer is better.
Because California is such a big state, firewood often is moved around without inspection by private individuals. Moving wood moves pests with them.
Watch out when you bring firewood indoors, too, warned Lee. "There are lots of possibilities for bringing things in with the wood. Watch out for spiders."
Firewood helped spread the pathogen that causes sudden oak death throughout Northern and Central California. It's also suspected in the transport of the gold-spotted oak borer, a penny-size bug covered with gold flecks.
"That borer affects all species of oaks but prefers larger oaks," Greenwood said. "That's why it puts our big trees at such risk. In November, we saw it jump from San Diego County to Idyllwild in Riverside County. It's very, very likely it moved in firewood."
The shothole borer isn't as picky; it eats all sorts of trees. Once unknown in California, this tiny black beetle attacks trees en masse.
"The tree looks like it was blasted with a shotgun," Greenwood explained. "There are lots of tiny holes in the trunk. You'll see drips of sap or piles of sawdust.
"Nobody knows where it came from, but suddenly it's here," she added. "It's quite worrisome."
Asian citrus psyllid has landed in the Los Angeles suburbs and traveled as far north as Tulare. This bug carries huanglongbing, a disease also called citrus greening. It has wiped out thousands of acres of citrus in Florida and Brazil.
"This is a pest nobody wants," Greenwood said. "Citrus is such a huge component of our urban forests. Every backyard tree is at risk."
This bug can be relatively easy to spot.
"These insects bend at a 45-degree angle," Ingels said. "The tree looks yellow and there's a twisting of small leaves. The challenge is a tree can be infected for a year or more before showing symptoms."
Lawn-destroying Japanese beetles, common on the East Coast, were trapped in Fair Oaks in 2011 and 2012. Diligence by state agriculture officials and homeowners kept this infestation contained to a small area.
If you see any of these insects, call your county agricultural office to report it.
It's too late to eradicate some bugs; they've already made themselves at home here. But winter diligence can help minimize their impact.
Dormant oil sprays applied now can stop scale, soft insects that sap plants and trees of their strength. Kuno scale, for example, attacks stone-fruit trees. Black scale likes olives.
Most scales attract ants, which "milk" the soft-bodied insects for their honeydew. Controlling scale helps control ants.
Codling moths and other destructive bugs can overwinter in the debris under trees. To help break their cycle, dispose of fallen leaves and fruit.
"Those leaves are harboring pests," Ingels said. "They need to be cleaned up."
A recent newcomer to California, spotted-wing drosophila, a tiny fly that attacks cherries, has had devastating effects on backyard trees. Winter cleanup may cut down its population.
Now may be a good time to attack another pest: voles. With voracious appetites, these mouselike rodents live underground but create visible runways to their shallow burrows.
"We've had a huge surge in voles, particularly in the Folsom area," Lee said. "You can see their runways between holes. Put out mousetraps along their paths. Their sight is very poor; they'll run right over the trap."
WINTER CARE WORKSHOP
Where: Fair Oaks Horticulture Center, 11549 Fair Oaks Blvd., Fair Oaks
When: 9 a.m.-noon today
Details: http://cesacramento.ucdavis.edu, (916) 875-6913
Sacramento County master gardeners will be out in force for this workshop as they demonstrate pruning techniques, tool care and selection, composting and other winter tasks. Got a garden dilemma such as a mystery pest or plant malady? Bring a sample in a sealed plastic bag for identification and diagnosis.
MASTER GARDENERS WORKSHOP
Where: Veterans Memorial Building, 130 Placerville Drive, Placerville
When: 9 a.m.-noon today
Details: http://ceeldorado.ucdavis.edu, (530) 621-5512
El Dorado County master gardeners share their Top 20 gardening hints with tips for successful seed starting, propagating by cuttings and divisions and other ways to get the most bang out of your gardening buck. The master gardeners also will be on hand to answer questions about pests and plant problems including how to protect your fruits and vegetables from birds and squirrels.
SEE MORE PESTS
www.ipm.ucdavis.edu: The state's go-to source for integrated pest management. Solve pest problems with the University of California's best science and latest research; very detailed with lots of photos and illustrations plus suggestions on how to control these pests, indoors and out.
Firewood.ca.gov: The official website of the California Firewood Task Force details which pests to look out for and why firewood should stay close to its origin.