Nemesis, the Greek goddess of vengeance, is said to be a ‘personification of the gods' retribution for violation of sacred law’. I would like to know what horticultural commandment I flouted to deserve a visitation, nay, a plague of stink bugs on my tomatoes.
My garden is adjacent to a large thicket of blackberries, which are reputed to be a stink bug magnet. I also have two large comfrey plants in the garden. These attract large numbers as well. But the insects are not content with such fare. They attack the tomatoes ruthlessly, vectoring diseases with their mouthparts.
I have determined that the culprit is the Conchuela stink bug (Chlorochroa ligata (Say)). This stink bug ranges from olive green to grayish brown with an orange margin along the thorax and wings and a spot of similar color on the scutellum.
Stink bugs, when not viewed through the filter of an irate gardener, are interesting insects. When disturbed they release a strong, unpleasant smelling liquid as a deterrent to predators. The smell is faintly almond like, owing to the cyanide compounds present. The family (Pentatomidae) is diverse, with some predators and several very colorful members.
Any infestation of this magnitude causes me to review my organic policy. I have never sprayed any synthetic pesticides in my garden and would prefer not to start now. But stink bugs are famously difficult to control using organic methods. In fact, in the most ideal of circumstances, the best control one can expect is 30-50%. Still, I cannot bring myself to resort to the heavier control methods so I will attempt some partial control this fall. Stink bugs overwinter as adults so the population of nymphs (immature stink bugs) is quite high in the fall, making this a good time to spray insecticidal soaps. These products can reduce the nymph population but are ineffective in controlling adults.
The issue of organic versus synthetic control is a contentious one, with arguments deteriorating to acrimonious name-calling on some of the garden forums I visit. I think it is really a matter of personal preference. Chemicals are chemicals and organic pesticides can be just as toxic as their synthetic brethren, despite their botanical origins. It is more a continuum of available options. If I start with the most benign option and it produces results I have saved myself time and money.
Still, I may be moving the tomatoes to a community garden plot next year. Options are not necessarily linear and when I reach the fork in the road where I must choose between the heavier poisons and relocation I think I know which path I’ll choose.