- Author: Ben Faber
Argentine Ant is a very aggressive invader that disrupts native ant populations and at the same time disrupts biocontrol agents that help control, such pests as scale, aphids and mealy bugs in citrus and other tree crop species. They defend these sugar producing sources of energy from attack by predators and parasites, like parasitic wasps and predatory assassin bugs and lady bugs. They increase the threat of Asian Citrus Psyllid and HLB by protecting the psyllid from attack by parasitic Tamarixia.
A careful, well placed chlorpyrifos spray has been used to control Argentine ants. A trunk spray and/or spray on irrigation lines has disrupted their activity with minimal impact on beneficials. This protectant spray keeps the Argentine ants out of the canopies and allows the beneficials access to the pests. Controlling this one species, can have significant impact on biocontrol and the whole need for controlling pests.
Chlorpyrifos is a pesticide that might lose registration and other materials and techniques have been examined over the years as a replacement. A recent procedure has been proposed and used successfully on Santa Cruz Island to control introduced Argentine ants. The ant has caused tremendous disruption in biocontrol and it appears to have been controlled by this new technique. We are in the process of evaluating it's use in citrus. The application technique, costs and materials would need to be modified for use in citrus orchards. The current procedure would not be considered an organic practice since the pesticide material is not registered organic. It might be possible to use an organically registered material in the future.
Protocols for Argentine ant eradication in conservation areas
L.Boser1,C.Hanna2,D.A.Holway3,K.R.Faulkner4,I.Naughton3,K.Merrill5,J.M.Randall1,C.Cory1,D.-H. Choe6 & S. A.Morrison
Journal of Applied Entomology
http://onlinelibrary.wiley.com/doi/10.1111/jen.12372/full
The Argentine ant (Linepithema humile) is a widespread, abundant and ecologically disruptive invader that is present throughout major portions of coastal California and on half of the California Channel Islands. On Santa Cruz Island, the Argentine ant had invaded about 2% of the island's area in four distinct locations as of 2012. Given the negative ecological effects resulting from Argentine ant invasions,we sought to develop a cost-effective method of eradication. Here, we describe the results of large-scale, field-tested methods for Argentine ant eradication and post-treatment detection. Our eradication protocol employs a novel toxicant-delivery system: an aqueous solution of sucrose and 6 ppm of thiamethoxam mixed with hydrating polyacrylamide beads. Ants feed on the solution present on the bead's surface for about 24h after which time bead dehydration prevents feeding. We distributed hydrated beads by helicopter over 74 ha of infested areas plus a 50-m buffer on 14 occasions between June 2013 and September 2014. Treatments reduced Argentine ant activity to subdetectable levels within four months. In 2014, we conducted a high-intensity detection protocol using lures (n = 55 363) in areas treated in 2013.This effort did not detect Argentine ants. In 2015, we conducted a medium-intensity detection protocol using lures (n=2250) in areas treated in 2013 and 2014 but not searched in 2014; this sampling effort did not detect Argentine ant activity except for a single remnant infestation (c.0.3ha in area),which was retreated in2015.Thec ost of treatments was approximately $1400 per ha; this cost is comparable to other ant eradication efforts. The cost of our preferred detection method, which used lures spaced every 10m,was $500 per ha.These results demonstrate sufficient protocol efficacy to justify expansion of treatments to other infested areas in ecologically sensitive areas.
Photo: Argentine ant and scale
Ants often enter buildings seeking food and water, warmth and shelter, or refuge from dry, hot weather or flooded conditions. They may appear suddenly in buildings if other food sources become unavailable or weather conditions change.
One such ant we see headed indoors during rainy conditions in California, is the Argentine ant. The Argentine ant is about 1/8 of an inch long and dull brown in color. It's normally found living in the landscape in shallow nests, and might even be living just outside your building. When rainy weather floods their nest, Argentine ants may use your home or office as a warm and dry place to relocate.
This rainy season, before ants have a chance to invade your home, be proactive and “ant-proof” your buildings ahead of time Determine what the ants are attracted to and eliminate the food or water source. Monitor the places in and around your home where ants are often found. Follow ant trails to find where they are entering, and seal them off using caulking or other sealants.
Of the 270 species of ants in California, fewer than a dozen are pests, and although ants can be bothersome pests indoors, it's important to remember that outdoors they sometimes also play a beneficial role in the environment.
Visit the Ants section of UC IPM's home and landscape web pages for more information about preventing or managing ant invasions. There you will find videos about ants including, “What to do if you have an ant emergency” and “Why do ants invade?” as well as other resources to help identify ants and know what to do indoors or out.
- Author: David Robert Haviland
The bugs belong to a family of insects called lygaeids that are commonly referred to as seed bugs. Seed bugs use their straw-like mouthparts to extract moisture and nutrients from a wide range of plants, especially ones with seeds. The specific species of insects being found in Ridgecrest and surrounding areas is called Melacoryphus lateralis. It does not have a common name. This bug is very similar in appearance to other insects in the families Lygaeidae and Rhopalidae, such as the boxelder bug and milkweed bugs. It is not a beetle.
M. lateralis is found throughout the western United States and is most common in desert areas of Arizona, Nevada, Texas, and southern California. Immature and adult insects feed on native desert plants and then fly to find new feeding sites or mates when they are adults. Adults are highly attracted to lights and can fly long distances, especially in search of succulent plants on which to feed as desert plants become dry during mid-summer.
Populations of this insect vary from year to year with outbreaks most commonly reported in the Sonoran Desert areas of Arizona in years with elevated monsoon-like weather associated with above-average rainfall. In the areas around Ridgecrest, above-normal populations of this pest in 2015 are likely the result of a mild winter followed by above-normal rainfall in February that provided ample food for nymphs throughout the desert. Then, in July and August, the combination of drying host plants and the attractiveness of lights has caused mass migrations of the bugs to urban homes and landscapes.
Management of the bugs is difficult due to the migratory nature of adults. Pesticides that kill insects on contact, such as home perimeter treatments used by licensed pest control companies, can provide excellent control of bugs that they come in contact with, but are unlikely to have any residual effects after one or two days. Businesses and homeowners are encouraged to keep doors closed and turn off lights whenever possible after dusk to reduce the risk of attracting bugs. Once bugs get inside structures, vacuuming is the preferred method for their removal. Outdoors the bugs can be swept with a broom or blown away from business entrances, porches, or parking lots with a leafblower.
Nobody is certain how long the insects will be around. However, reports from Arizona suggest that aggregations of adults occur in July and August, which suggests that populations are likely to become reduced over the next few weeks. These reports also suggest that the outbreaks that are occurring in 2015 are likely a one-time anomaly that won't repeat itself again unless the favorable environmental conditions for the bugs are repeated. For the sake of Ridgecrest residents, let's hope that doesn't occur.