Beauveria bassiana

Madeline Campbell - Ecuador

May 24, 2012

For the last month or so I’ve started working exclusively in the microbiology lab here at AACRI, which I absolutely love.  The lab is where we cultivate fungus and bacteria to make organic fertilizers (hence the name ‘organic’ coffee) and treatments for coffee and cacao plants.  We don’t actually grow cacao here, but we sell our products to organizations and farms across Ecuador that do.  Among the products we produce in the lab is a fungus called Beauveria bassiana that is found naturally in the environment.  This fungus is valuable because it controls the coffee-borer beetle, or coffee berry borer (say that five times fast), which is considered one of the most harmful pests to coffee growers worldwide.  It was originally native to Africa, but in the past decade has spread to many parts of the globe, including Hawaii, the U.S.’s only coffee-producing state, and Ecuador.

How does this little friendly-looking fungus work to control the pest?  What it does is it causes something called White-Muscardine disease.  When the spores of the fungus come into contact with the cuticle of the host insect, it slowly grows on the body of the insect, in it’s joints, through the cuticle, into the body and eventually kills the insect in a matter of days.  The end product looks something like this

Beauveria b. on the body of an infected insect.

That particular picture isn’t actually of a coffee borer beetle, but rather something else….which is important, because this fungus affects many types of insects, mostly those considered pests by humans and farmers.   Remember Japanese beetles? Those iridescent greenish black beetles that plagued your garden every summer (depending on where you live)?  They’re affected by this fungus.  Termites too.  And grasshoppers, aphids, whiteflies, the Colorado Potato beetle, the Mexican Bean beetle, European corn borer, chinch bugs, fire ants, bark beetles, and Douglas fir tussock moths to name a few.[1]

The exciting part is that certain labs around the globe have begun researching the possible use of this fungus to control malarial mosquitoes, and thereby controlling the spread of malaria in high-incident areas around the globe.  Because this fungus occurs naturally in soils all over the globe, the possibility of it becoming invasive and causing environmental disruption may be lessened.  It is not considered harmful to humans (minus one recorded incident of a lung infection in an individual with a suppressed immune system[2]) and when used correctly is generally non-toxic to beneficial insects.[3] These, among other factors make it’s use as a malaria control a desirable possibility.  Especially when compared to DDT, a chemical insecticide used throughout the 20th century in agriculture and in WWII to control Malaria and typhus among troops.  It was banned in 1972 and is now known to be extremely harmful to humans and the environment[4]. If we can develop effective methods of using B. bassiana to control mosquitoes, it could become a powerful contender in the global fight against malaria.

In my apprenticeship here in Apuela we use this fungus to control the coffee borer and nothing else.  I never thought of it as any more than some white stuff in a dish until this. The more geeky part of me likes to imagine that I’m working with a celebrity…of sorts.

Madeline Campbell