Invasive Insects

Invasive species often spread rapidly, and they are likely to be more damaging in their new environment than in their original location. One such invasive insect species that is considered North America’s most destructive insect is the emerald ash borer, a beetle thought to have entered this continent from Asia in wooden pallets from China. In less than a decade, the emerald ash borer has killed tens of millions of ash trees and threatens to eliminate all North American ash species. The efforts to identify and control this invasive insect are detailed in a New York Times piece, http://www.nytimes.com/2011/09/13/science/13beetle.html. Often, invasive species have their populations held in check in their native environment by pests, pathogens, or competing species. Without these limiting factors, the populations of an invasive species may explode across its new range. That seems to be happening with the emerald ash borer following its discovery near Detroit in 2002. To follow the spread of the beetles, now in 15 states and adjacent Canadian provinces, the Forest Service developed a purple-colored, scented beetle trap to locate the invasive insects. Control of the beetles using insecticides is considered too costly for North America’s more than seven billion ash trees. While biological controls are being investigated, a control strategy using “sink trees” is being used. A few ash trees are intentionally killed and used to attract emerald beetles. These trees are then cut in the winter killing the beetle larvae. In today’s photo, rows of green ash and oak trees stretch for sunlight above annual grasses in Peace Farm’s Wetland Reforestation Project. The trees will protect a tributary of the Mississippi River from erosion.

The spread of emerald ash borers has occurred at the same time as small hive beetles spread through bee yards across the states. Effective methods of control of the rapidly spreading small hive beetle will rely upon cultural, biological, and mechanical methods. It is too dangerous to the bees to use insecticides inside bee hives.

--Richard

Eat Invasive Species?

Through photosynthesis, plants convert solar energy into carbohydrates forming the basis for a food chain that sustains all living creatures. Agriculture provides our most efficient usage of solar energy, and the honey bee is an integral part of agriculture. Without the bees and other pollinators, the diversity of plant life and food for wildlife, livestock, and humans would be greatly reduced. The January 2011 issue of National Geographic features in-depth coverage of the planet’s expanding human population, which is expected to reach seven billion this year and nine billion by 2045. The rapidly growing population will make an increasing demand upon the earth’s resources. The future will see increasing challenges in feeding the world. A New York Times article describes some novel, sometimes whimsical, approaches to solving two of our challenges: obtaining food and controlling invasive species. As food for thought, literally, the author challenges us to find ways to reduce the invasive plants and animals by finding ways to make them desirable food choices. He describes how chefs in the Florida Keys are preparing invasive lionfish and Chicago chefs are cooking invasive Asian carp. Individuals in other parts of the country are anticipating an abundance of invasive members of the mustard family in the spring. The incredibly fast-growing kudzu vine, an invasive legume imported to control soil erosion, is known as a food source. While these plants are considered a nuisance to some, they are important bee plants, producing both nectar and pollen. I have eaten delicious kudzu honey produced in Mississippi. The Times piece, “A Diet for an Invaded Planet: Invasive Species,” can be read at nytimes.com/2011/01/02/weekinreview/02gorman.html?_r=1&hpw.

Many people enjoy eating wild game. A number of states have programs that provide venison donated by hunters to feed the needy. A generous friend recently donated a flock of geese to provide sustainable nutrition for a distant family through Heifer International. Visit http://www.heifer.org/ to learn about their programs. Today’s photo: gently, domestic Toulouse geese noisily greet Peace Farm visitors.

--Richard

Small Hive Beetle Invasion

The small hive beetle probably entered the United States like many invasive species as a stow-away in a cargo ship. The unintentional migration of this honey bee pest from Africa occurred about a decade ago. The beetle entered the Arkansas Delta about 2004. As the beetle is virtually unchecked by any natural predators, it spread rapidly to almost all parts of the country. This invader is thought to be capable of flying for miles, and it is moved with migratory bee hives on trucks.

The small hive beetle is an opportunistic invader of bee hives. The adult beetle, about a third the size of a lady beetle, can live inside the bee hive, protected from the bees by a hard covering. The beetles often occupy a healthy hive and wait to move to a weakened, stressed, or queen-less hive. The small hive beetles are attracted to a stressed hive by the alarm pheromone given off by honey bees. Inside the stressed hive, the small hive beetles lay eggs. The beetles develop through a full four-stage metamorphosis like the honey bee. It is the second stage of the small hive beetle’s development that damages the honey bee hive. The small hive beetle larvae eat everything in the hive: comb, brood, pollen, and honey. They turn the hive into their waste, a wet, brown slime with the odor of fermenting oranges. The odor attracts small hive beetles from miles around and repels honey bees. Bees will abandon the slimed hive, often in a manner of a few days. Click on the photo of small hive beetles starting to take over a queen-less hive. The first sign of trouble that I detected was bubbles developing in the fermenting honey in the supers above the brood nest. Fermenting honey is in the cells to the upper left. Caught early, before the combs are slimed, the beetles may be killed by freezing the frames.
--Richard

Fire Ants: An Invasive Pest

While examining a bee hive, I dropped a frame of bees and brood. Actually, I didn’t drop the frame; I really threw it back into the hive. A good beekeeper knows to always maintain a good grip on everything associated with a bee hive. Both embarrassed with myself and maddened, I looked to see why I did this. I saw that both of my hands were covered with stinging fire ants. These invasive fire ants are moving through the Arkansas Delta. I found the first two fire ant hills on Peace Farm three years ago. The following year, I found a dozen. By the next year there were hundreds of the over foot-tall ant hills. Now I am finding the fire ants living in our bee hives. The fire ants are establishing colonies between the outer and inner covers of the bee hives. In the photo, you can see the red and dark brown fire ants carrying their larvae past the half-inch tall letters left on our equipment by our branding iron. Two fire ants, social creatures, share the task of carrying one larva.

It is always difficult to control an invasive species. Plants or animals that are introduced into a new ecosystem often lack the creatures that helped regulate their populations in their original location. The fire ants may be replacing native ant species, which we try to protect and use as part of our integrated pest management program. There are insecticides available for use against fire ants. These may be effective; however, there is always the possibility of pests becoming resistant to chemical agents. Mechanical or biological control measures often prove to be better over time. There are few ways to mechanically control fire ants, which live deep in the soil. An educational partnership of universities in the United States, called eXtension, reports on a biological control being tested using a natural predator of the fire ant, the phorid fly. You can get more information about fire ants and see some of the research approaches being used at their web site, http://www.extension.org/fire+ants. I know that I will be doing some more research. Right now, the fire ants seem to have the upper hand.
--Richard