Tag Archives: Pests and Diseases

The innocent pyrethroids, perspectives from the bottom of the ag drainage canal

17 Jan
English: Pumping station A drainage channel le...

. (Photo credit: Wikipedia)

Hello, gentle readers,

I am writing to announce that I have actually started working in my field, or more precisely, in the canals at the end of the irrigation ditches at the downhill side of my field, and I am thrilled. My job is to sample water to help California growers comply with state and federal regulations regarding nutrient and pesticide loads in their tailwater. I have no skill getting my waders un-stuck from the mud, so I only hope one day to go pro, but this is my big chance, I think.

From a debriefing session at the company headquarters I learned that there are exceedences for two organophosphate pesticides, a family of pesticides effective against many insect pests and very soluble in water. Instead, to protect waterways from further contamination, farmers are switching to more frequent use of pyrethroids, a family of pesticides extracted from the marigold family of plants and effective against a narrower range of pest insects, namely the butterfly and moth family. Pyrethroids were considered safe because they bind to soil well and they break down fairly quickly, but if they do wash down into waterways on sediment particles, they are deadly to aquatic invertebrates, and they need to be used more frequently than their organophosphate predecessors. Is switching to pyrethroids really an improvement? I have my doubts.

Am I glad to be doing something about my passion for public access to environmental quality data? You betcha!

From the ditch,

Your faithful correspondent.

Pest management for your sweetie: Cacao Pesticide Public Relations poster–Thoughts?

22 Mar
A Russell Stovers box of milk chocolates.

A Russell Stovers box of milk chocolates. (Photo credit: Wikipedia)

2-ValentinesPoster

An industry poster (above) shows a picture of a heart-shaped box of chocolates with all but one of the chocolates missing, a vivid depiction of the impact of pests, particularly a fungus commonly known as black pod disease, has on this tropical crop where no pest control is applied. The poster advocates for “modern agricultural approaches”, implying that the chemical industry should be thanked for the rest of the box of chocolates in the image, the chocolate harvest to which we have become accustomed (example at right).

I researched the pest management options available to cacao growers and found that black pod disease is one of the primary pests in cacao, resistant varieties of the crop are not resistant enough to ward off the disease, beneficial fungi such as Trichoderma give about 50% control of the pest, but fungicides like Kocide give almost complete control of the pest.
title=”Deberdt2008CacaoIPMarticle”>http://www.worldcocoafoundation.org/scientific-research/research-library/documents/Deberdt2008.pdf

FAQ:
1. What is this fungicide, Kocide? Copper Hydroxide.

2. Who makes it and what kinds of precautions should be taken when using this material? This is a basic salt of copper and it is most hazardous if you inhale it, causing lung and kidney problems. It is also very hazardous to inhale as a gas if it were exposed to fire. Handlers should wear long sleeves and protection against breathing the wettable powder or the spray.

3. Does it harm nontarget species? How long does it stick around? Copper hydroxide is very toxic to aquatic invertebrates like daphnia, the classic ‘canary in the coal mine’ of water bugs. This substance should not get into waterways, and empty containers need to be disposed of as hazardous waste because it is a heavy metal and is regulated as hazardous waste. Copper binds tightly to the soil and may reside there for a long time in a not-very available form, but repeated use of this pesticide might result in buildup of this naturally occurring metal in the soil.

OP-ED: What are the implications for chocolate growers around the world?
Deberdt’s article mentions that most farmers in Cameroon, a cacao growing country, cannot afford the chemical fungicide and may experience up to 100% loss of their crop, validating the poster’s depiction of the losses that the untreated disease can cause. Copper hydroxide is a real option for improving yields and livelihoods of these farmers and they probably would use it if they could afford it. Biological controls like beneficial fungi might be a good compromise because they have some carry-over effects to the following year, so farmers can buy them every few years and get some relief from the black pod disease. I actually do agree with this industry poster and feel that this particular fungicide, if used away from waterways and if care is taken to prevent inhaling this product, can make a big difference in the lives of growers and I will still eat cacao!