Friday, October 26, 2012

Superweeds and Superpests

The use of genetically modified crops was intended to reduce the need for herbicides to control weeds and insecticides to control pest insects. However, The New York Times reports that instead herbicide use increased over 16 years, while insecticide use decreased somewhat. The widespread use of a single herbicide glyphosate, sold under Monsanto’s brand name Roundup, has resulted in the evolution of a number of glyphosate-resistant weeds. The Times piece,, describes different approaches to the use of these genetically modified organisms. “Roundup Ready” corn, soybeans, and cotton seeds were planted on 1.37 billion acres from 1996 to 2011. The GMO plants, tolerant of the herbicide glyphosate, were supposed to reduce or eliminate the need to till fields and reduce the need for harsher chemicals. The use of these GMOs was supposed to also save money and be less stressful on the environment. As glyphosate-resistant weeds increased, increases in the use of glyphosate slowed; and in 2010 the National Research Council warned that, “Eventually, repeated use will render glyphosate ineffective.”

Those deploying the genetically modified seed containing the Bt gene producing toxins from the soil bacterium Bacillus thuringiensis recognized the potential for evolving resistant insects, and they took precautions. They required that a percentage of non-Bt seed be planted with Bt crops to ensure that some insects susceptible to the Bt toxin survive to mate with survivors of the Bt crops. Otherwise, surviving pest insect populations could become increasingly resistant to the Bt toxin with each generation. The mechanism for ecological harm from chemical pesticides was described by Rachel Carson in Silent Spring 50 years ago: “First, many of these chemicals are indiscriminate, killing not only pest but also the predators and parasites that help to keep them at bay. Second, surviving pest populations become increasingly resistant to the applied toxins with each generation, as those most susceptible to the toxins die off. It’s natural selection in overdrive.” Today’s photo: applying herbicide to control grasses in GMO soybeans.

Friday, October 19, 2012


Three types of bee hives are used in Ethiopia. Ninety-seven percent of the hives are traditional hives, long baskets built at no expense of cane and banana leaves. These hives are usually hung high in trees, but they are also attached to the outside walls of houses. Some traditional hives are placed inside houses under beds. Modern bee hives similar in design to the Langstroth bee hive comprise two percent of Ethiopia’s bees. The remaining one percent of Ethiopian bee hives is top bar hives, described as “transitional hives.” These simple boxes are also built from locally available materials at no expense. Transitional hives provide an economical method of managing honey bees that allows for the benefits of modern beekeeping: ease of hive inspection, ability to combine and divide colonies, move brood between hives, requeen, and improve genetics. Most importantly, transitional hives allow for the non-destructive harvesting of high quality honey. Beeswax is harvested by crushing honeycombs. Hive products are collected without killing or losing the honey bee colony. Today’s photo from Ethiopia shows one of Teshome’s transitional bee hives mounted in a tree. This top bar hive is covered in plastic and foliage as is the custom in Ethiopia. I recommended that Teshome consider removing the foliage to improve air circulation. Chalkbrood, a honey bee fungal infection, is a major hive problem in Ethiopia’s rainy season.

Many transitions are occurring on Ethiopian farms. Beekeepers earn additional income with transitional and modern bee hives. Using standardized sized hives, beekeepers can move combs from one hive to another. Teshome recognizes the benefits of improving queen bee genetics; he uses similar techniques in cattle breeding. He foresees the ability to produce gentler bees by selecting queen stock from his best hives. His farm is steadily transitioning to a broader based economy. Teshome eagerly traces the design of my hive tool so that he can have the local blacksmith produce tools for area beekeepers to take a more hands-on approach to beekeeping.

Sunday, October 7, 2012

Biological Controls

Before embarking on my latest beekeeping trip to Africa, I checked the hive that I was using to transfer a colony of feral honey bees from a hollow tree. All was progressing well, the capture hive was full of bees; the bees even filled two honey supers with summer honey. When I returned a few weeks later, the hive was completely “slimed” by small hive beetle larvae; the bees had abandoned the hive; and the honey was fermented. The hive was overtaken by small hive beetles. Bees and beekeepers find invasive small hive beetles difficult to control. Currently, chemical and cultural controls are used to reduce small hive beetle populations.

Researchers at the University of Arkansas asked a question: Could the small hive beetles have brought their own parasites with them when they entered the US? The presence of such a parasite of the small hive beetle could possibly lead to a biological control for these bee hive scavengers. To investigate the possibility that there may be a not-yet-discovered parasite, Natasha Wright collected small hive beetle adults and larvae and samples of soil from bee yards in Arkansas and adjacent states. She dissected 749 adult beetles and 230 larvae from 13 counties in Arkansas and one county each in Oklahoma and Missouri. Natasha found no microbial pathogens in the SHB larvae, but she did find a protozoan pathogen in adult SHBs from three Arkansas counties. Most of the infected beetles were from a single apiary in nearby St. Francis County, Arkansas. One infected beetle was found in a Peace Bee Farm apiary in Crittenden County, Arkansas. In total, 5.3 percent of the adult beetles sampled were infected with the protozoan pathogen, which forms cysts in the beetles’ Malpighian tubules. The heavily infected beetles detected in St. Francis County were described as having an “impaired function in life.” Hopefully, research will find safe and effective controls for small hive beetles. For published results: Today’s photo: SHB larvae slime a hive.