Despite the natural history and taxonomic focus on beetles and other insects I have adopted for this blog, I am by day an agricultural research entomologist.  For the past 15 years soybean entomology has been my focus, and there is no better nexus for soybeans and entomology than South America.  Cultivated hectares have increased dramatically in Argentina and Brazil over the past several decades, now totaling nearly 80 million acres in those two countries alone (roughly the same area as in the US, by far the world’s largest producer of soybean).  Unlike the US, however, where insect pressure is minor outside of a small number of acres in the southeast, significant pressure occurs in nearly 100% of South America’s soybean acres.  Lepidopterans, primarily species in the family Noctuidae such as velvetbean caterpillar (Anticarsia gemmatalis) and soybean looper (Pseudoplusia includens), are the most important pests, followed closely by stink bugs.  This latter group is especially problematic for growers to deal with.  Stink bugs feed on the developing seeds, causing direct yield impacts through reductions in weight and quality, and because they are a guild of insects rather than a single species, differences in product efficacy against the different species can lead to ineffective or inconsistent control.  I’m involved in trying to do something about this, and while I hate to be deliberately coy, suffice it to say that there is an awful lot of insecticide being sprayed on an awful lot of acres and that the world really would be better off if this weren’t the case.

During my recent visit to Argentina this past March, I took advantage of the opportunity while touring soybeanland to photograph a number of these stink bug species.  Proper identification of stink bugs in a crop is the first step towards controlling them, thus I present here my own photographic guide to some of the more important stink bug species found on soybean in Argentina.

Nezara viridula (chinche verde), adult | Pergamino, Argentina

Nezara viridula, 5th instar nymph | San Pedro, Argentina

Nezara viridula, 1st instar nymphs on egg mass | Oliveros, Argentina

Piezodorus guildinii (chinche de las leguminosas), adult | Pergamino, Argentina

Piezodorus guildinii, 1st instar nymphs on egg mass | Acevedo, Argentina

Edessa meditabunda (alquiche chico), adult | Acevedo, Argentina

Edessa meditabunda, 1st instar nymphs on egg mass | San Pedro, Argentina

Edessa meditabunda, eggs nearing eclosion (note eye spots) | Oliveros, Argentina

Euschistus heros (chinche marrón), adult | Oliveros, Argentina

Dichelops furcatus (chinche de los cuernos - note two ''horns'' in front), adult | Inés Indart, Argentina