Monday, September 1, 2014

Every Season is Ant Season

When it gets hot, the ants start marching indoors. When it rains, in come the ants. Too cold? The ants know where its nice and cozy: your kitchen, bathroom and pet food bowls. Outdoors, the pet food bowls and garbage cans are also ant attractants. Argentine ants, those busy little black ants, are in march formation year round.

In years past, we would reach for the spray can and douse those little scavengers. But not anymore.

 Many of those spray pesticides are only effective with direct contact on the ants. And the stronger sprays, with residual action to thwart the next wave of ants, is potentially harmful to you, your kids, your pets.

So, here is what we are doing now: following the recommendations of the UC Davis Integrated Pest Management Project for Ant Control.

That includes:

• Determine what the ants are attracted to and remove the food source
• Vacuum trails, wipe them with soapy water, or spray with window cleaner
• Locate entry points and caulk openings or plug with petroleum jelly
• Put out bait stations with liquid ant bait or apply gel bait at entry points
• Baits take time to work so continue to clean up trails
• Indoor sprays are not usually necessary.

• Avoid products packaged as granules that contain the active ingredients cyfluthrin or permethrin. Although these products may be mistaken for baits, they are actually contact insecticides that rapidly kill foragers and do not control the colony.

Before wiping up (or wiping out) the little critters, follow their trail. Note their entry point into the house. Seal it up. We have found ants entering the house in a variety of small avenues: beneath moulding, cracks in the window frame, behind electrical outlet plates...and one of the ants' favorite entries: that large holes beneath the sink where the pipes enter the house.

According to the UCD IPM page on ant control, "If ants can be thoroughly washed away and excluded from an area, an insecticide is probably not necessary. Vacuuming up ant trails or sponging or mopping them with soapy water may be as effective as an insecticide spray in temporarily removing foraging ants in a building because it removes the ant’s scent trail, especially if thorough cleaning is done at the entry points. Some soap products such as window cleaners can kill ants on contact but leave no residual toxicity. Certain plant-based oils are also applied for this purpose, but their odor can be offensive."

Oh, and another lesson we learned the hard way: if you put those ant baits indoors, you will attract more ants inside. Look for ants crawling along the outside of the house, and place the baits there, being sure to follow all label directions.

What about those ant sprays that are intended to be used as a perimeter spray along the outside of the house? Stick with the bait traps, says the UCD IPM page: "Spraying around the foundation will not provide long-term control because it kills only foraging ants without killing the colony. Perimeter treatments may appear to knock down the population, but ants will quickly build back up and invade again. To try to achieve long-term control, some pest control companies offer monthly perimeter spray programs. Perimeter treatments pose more risk of environmental upset than baits in bait stations and are less effective than a bait-based IPM program."

Ant baits are not ant traps, even though some ants may be stuck there. The whole point of ant baits: they get the stuff on them, take it back to their nest, where they share it with others...and then croak. Be patient. It may take a week or so for the baits to work on the ant nest.

More info about ant baits from the UCD IPM project: "Baits are insecticides mixed with materials that attract worker ants looking for food. They are a key tool for managing ants and the only type of insecticide recommended in most situations.  Ants are attracted to the bait and recruit other workers to it. Workers carry small portions of the bait back to the nest where it is transferred mouth-to-mouth to other workers, larvae, and queens and other reproductive forms to kill the entire colony. Bait products must be slow-acting so that the foraging ants have time to make their way back to the nest and feed other members of the colony before they are killed. When properly used, baits are more effective and safer than sprays."
• Sweet sugar baits such as boric acid (use low concentrations with less than 1% of the active ingredient) are highly attractive to Argentine ants throughout the year.
• Protein baits are attractive to ants in spring when colonies are producing new offspring. (Baits like fipronil or hydramethylnon are effective.)

• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home.

• Place baits near nests, trails, or along foundations, preferably in the shade.

• Baits should be placed in protected areas away from children and pets.

• Offer small portions of each bait to see which one is preferred before employing an extensive baiting program.

• Follow up regularly to make sure bait is working and place fresh bait as necessary.

How baits work:
• Worker ants are attracted to the bait and take it back to the nest where the entire colony, including queens, may be killed.

• Bait must be slow-acting so workers won't be killed before they get back to the nest.

• Results may not be evident for several weeks.

• Bait stations or ant stakes are easiest to use and safest for the environment.

Ant baits contain various active ingredients and attractants. We have tried a variety of different ones, to appease the finickiest of ant diners. Besides the Gourmet liquid ant bait, another one of my favorites is powdered boric acid in a squeeze bottle, another less toxic alternative.

But again, use it outdoors...otherwise, you will be drawing more ants inside.

Monday, August 18, 2014

Oak Galls, Bouncy Offspring Return in 2014

Dear Farmer Fred,

"Can you identify the pink and little brown balls growing now on our oak tree? I don't remember seeing these before.
Is it some kind of parasite? If so, what should we do? Thank you. We enjoy your weekly show very much." Margaret of Shingle Springs (CA)

Yep, it's oak gall season in California! Galls are interesting creations of several varieties of (usually harmless) wasps. No action is necessary on your part, except to enjoy the show.

The Integrated Pest Management Project at UC Davis says this about galls: "Most galls are caused by cynipid wasps and gall midge flies. The adult gall wasp is a small, stout, shiny insect with very few wing veins and a purple or black body. Adult gall midges are tiny, delicate flies, often with long, slender antennae. Galls are distorted, sometimes colorful swellings in plant tissue caused by the secretions of certain plant-feeding insects and mites. These unusual growths may be found on leaves, flowers, twigs, or branches. Most galls are not known to harm trees. Prune and dispose of galls if they are annoying. This may provide control of some species if pruning is done when the immature ones are in plant tissue and before the adults begin to emerge."

Retired state entomologist Baldo Villegas chimes in:
"Your picture of a blue oak tree have several types of oak galls made by several species of small, non-stinging wasps in the wasp family "Cynipidae". As an entomologist, we refer to the members of this family as "cynipid wasps". They are unique among the wasps in that they lay their eggs on plant tissue resulting in a distinctive plant gall encasing the egg/larva. Each cynipid wasp species make different and distinctive galls and one can identify them based on the gall type. Obviously, your blue oak sample had several types of galls and therefore several species of wasps. There is not much you can do to control these gall wasps. They are native species that co-evolved with the blue oaks in the area. The wasps are not killing the trees and they also don't appear to weaken them; so, my recommendation is to just let them be."

"1) The most obvious are the "echinid galls" produced by the wasp "Dryophanta echina".  These galls vary from pink to bright red and have the spiny galls.

2) The second gall that you asked for was for the small brown galls that look like little brown balls? These are probably "jumping oak galls" caused by the wasp "Neuroterus saltatorius."

Thanks, Baldo!

Other interesting oak galls:
And here's more fun with jumping oak galls...

  Lynn in Chico writes: "Yesterday I noticed my sidewalk was dancing, sort of.  Looking closer I saw what looked like bird seed scattered, but the seeds were jumping!  I collected a few of the tiny eggs (?) and they are still jumping this morning. They can get about a half inch of air when they jump.  I assume they are some sort of bug getting ready to hatch. Most of them are on the ground under the oaks on my property.  Please let me know if they are good bugs or bad bugs."

     Again, those would be oak galls, not a problem. Here is more info:
Jumping Oak Galls Are Interesting and Harmless to Oak Trees

by Ed Perry,  U.C.  Farm Advisor

"If you have a Valley oak tree growing in your landscape, or if you visit one of our local parks where Valley oak trees are growing, you may notice a strange phenomenon occurring this year. The ground beneath many Valley oaks this year is covered with pinhead-sized yellow or brown seedlike objects, most of which are hopping around. The tiny things are called "jumping oak galls", and are formed by a tiny, dark wasp. The wasp belongs to an interesting family of wasps called the cynipids.

"The galls are actually malformations of plant growth. The tiny gall-forming wasp lays an egg in an oak leaf at a precise moment in the treeís growth cycle, causing normal plant cells to multiply at an unusually high rate. As a result, the tiny egg becomes encased in the gall composed of oak leaf tissue.

"When the egg hatches, the gall provides both food and a living chamber for the larvae. In summer, the oak gall drops to the ground with the tiny wasp larvae inside. The insect moves in jerks, causing the entire gall to jump around on the ground. Itís believed that the larvae hop around in an attempt to find a crack in the soil to hide up in. At maturity it transforms into a pupae, and later into an adult which chews its way out of the gall. The wasps themselves are dark colored, so tiny that youíll probably never see them, and harmless to people.

"A few insect-formed plant galls are found on willow, poplar, rose and other plants, but more than 100 different kinds are found on oaks. The entire oak tree is fair game for the cynipid wasps, which form wasps on leaves, buds, twigs, branches, roots and even the acorns. Each cynipid wasp species forms a gall of particular size, shape and color; no other species forms one quite like it. Also, each one lays its eggs in a specific plant part.

"Besides the jumping oak gall, you be familiar with the common oak apple, a large gall up to three inches in diameter. These large galls are common on the deciduous Valley oaks, and contain one or more tiny cynipid wasp larva inside. You may also find a pink, star shaped gall on the undersides of Valley and blue oaks. Other galls are cone shaped, or round and fuzzy, or shaped like tiny loaves of bread.

"In California, most insect caused galls are not harmful to the plant. In some cases the galls may damage leaves or even cause twigs to die. However, the insect galls cause no serious permanent injury. Because of their complex life cycle, it is very difficult to prevent cynipid wasps from forming galls; in most cases, it is unnecessary to do so." 

Jumping oak galls (video courtesy of listener Darcy):