Ansel Oommen | Bugwood.org

Although PMPs often think of drywood termites as infesting the South, Southwest and West Coast, you never know when they might show up in your neck of the woods.

Because they need no soil connection, isolated drywood termite infestations (including Incisitermes, Cryptotermes and others) may arise in virtually any area since colonies can be transported inside furniture and other infested items — including musical instruments.

“I live in Ohio, which is not a normal range for drywoods, but they can move into furniture. And it could take them a number of years to swarm,” said Nicky Gallagher, technical services manager, Midwest and Northeast U.S., Syngenta Professional Pest Management (PPM). “Once a local PCO called us because he didn’t recognize the termites he was seeing. (His client) had a piano that was infested with termites. Thankfully they didn’t get into other areas of the house, and the piano was able to be treated.”

Because of this potential market opportunity, and because of PMP demand for additional products to use in the field, Syngenta announced in 2016 that Altriset termiticide had been labeled for drywood termites, in addition to eastern subterranean and Formosan termites. “To provide the PMP with greater flexibility in controlling termite infestations, the updated label also includes an expanded application rate range option to increase the amount of active ingredient per finished gallon of solution, from 0.05 percent to 0.1 percent,” Syngenta said. “Upon application, Altriset paralyzes the mouthparts of termites within hours of exposure, stopping further damage immediately. Its unique mode of action increases termites’ aggregation and grooming behavior, which allows affected termites to expose other colony members to Altriset. With an excellent environmental profile, Altriset used at labeled rates is sensitive to beneficial soil organisms, like earthworms.”

That environmental profile has taken off with PMPs and customers, Gallagher said. “Altriset is a targeted insecticide and has minimal impact on non-targets,” she added. “In California, where some customers tend to be more interested in least-toxic options, Altriset has really found a home.”


Drywood Termite Fast Facts

Subterranean termites are found in every U.S. state except Alaska.
Drywood termites are found mostly along the coastal regions of the U.S., extending from Virginia to Florida, along the Gulf Coast, through the Southwest and along the Pacific Coast from Mexico to northern California.
A subterranean termite colony can contain millions of termites, while a drywood termite colony often contains less than a thousand individuals.
Subterranean termites need soil contact to establish a colony, while drywood termites do not. Drywood termites have a more impermeable cuticle that retains body moisture, so they are well-adapted to drier environments.
Source: The Mallis Handbook of Pest Control

TREATMENT OPTIONS. Since drywood termites live solely within wood, no benefit is derived by chemically treating the soil. Control primarily involves killing drywood termites within the wood. Various approaches, both chemical and non-chemical, are available. Whole structure or spot treatments are options as well.

The most common form of whole-structure termite treatment is fumigation. Heat treatments are the other way to provide whole-structure single treatment eradication of drywood termites.

If the infestation appears to be limited and accessible, localized (spot) treatments are the approach for most PMPs. Such treatments are less costly and more convenient than whole-structure treatments.

The vast majority of spot treatments involve injecting chemicals directly into termite galleries. The “drill-and-treat” method for controlling termites has been used since the 1920s, according to the Mallis Handbook of Pest Control. With the drill-and-treat method, probing, sounding or other methods are used to detect termite galleries within wood. Once these areas are determined, the infested members, as well as nearby adjoining wood, is drilled. Mallis says research and practical experience suggest that non-repellent residuals are most effective for intra-gallery injection.

To control drywoods via spot treatment, Altriset can be applied as a liquid or foam treatment to penetrate localized infestations in difficult-to-reach areas. “For drywood termites, you can use Altriset as liquid or foam, but I think foam is really great because it can get into nooks and crannies — places we can’t see,” Gallagher said. “Additionally, PMPs can use a really wet foam or a really dry foam. You have flexibility in how you use it. Foam is more ideal for treating drywood galleries because it increases the probability that you’re getting the product where it needs to be.

“Unfortunately, when drilling and treating for termites, you don’t necessarily know where the product is going — you’re making an educated guess,” Gallagher said. “You might not get product to 100 percent of the area when you treat. However, with the benefit of a non-repellent termiticide like Altriset, the termites pass it along.”

She added, “While foam treatments are beneficial, a liquid termiticide treatment may provide more saturation of wood. I was really impressed with one of the trials in which we added a dye to Altriset and injected the liquid into logs infested with drywood termites. These sizable logs received minimal drill holes — only four to six per log.”

Gallagher said after they added the dye, they opened up the logs to see how far Altriset went. “Within a few weeks after treatment, all activity in the wood had stopped. We used an acoustic emission detector, which detects vibrations caused by termite feeding. Thirty days post-treatment, we opened the logs to see how far Altriset went, based on the dye placement. We found the product had only reached about 60 percent of the galleries, but we had 100 percent control.

Gallagher added, “Sixty percent coverage is excellent, as previous studies have shown that at least 10 percent of the gallery system needs to be treated to achieve effective control when conducting localized drywood termite treatments.”

ANOTHER TOOL. “A lot of our customers aren’t just dealing with subterranean termites, they’re dealing with drywoods too. Customers knew the benefits of using this product and it fits really nicely for customers wanting to use a green approach,” Gallagher said. “Syngenta wanted to present complete control options, not just treatments for subterraneans. Customers can have one product to fight the battle against both of those wood-damaging termites.”

“We’ve had good feedback (from customers),” she added. “Before we launched the label addition we had to test it and make sure was doing the job in the lab and field. With drywoods, Altriset does a fantastic job. In just a few weeks we see drywood termite activity go down.”