The evaluation of Bacillus thuringiensis against Heliothis spp. should be made under the conceptual embrace that each producer's field of his cotton crop is a fruit producing commodity. This commodity, as is well understood, has a sufficient genetic pool to initiate the production of more fruit than that crop has the potential to mature. Even under the most ideal field conditions, most cotton varieties can or will effectively mature only a fair fraction of the squares that the plants produce. Given this biological fact, total fruit protection by whatever means is an expense that where undertaken is ill-advised. Efficient cotton production does however dictate the need for fruit protection from certain pests at certain times, both of which are highly irregular in intensity or occurrence. Some Pests may be more regular in appearance and are usually noted as key pests. Others, the secondary pests, are the result of perturbations on the ecosystem and their occurrence is only generally understood. Heliothis spp. as economically damaging pests are a type species for created or induced pests. The fact that more of a grower's variable expenses are incurred for Heliothis spp. protection by chemical means than for any other single pest, bears witness to the amount of perturbation imposed on the cotton ecosystem by them, and their ecological implications in cotton production today.

Because Heliothis spp. has such a tremendous ability to damage cotton fruit, coupled with a genetic strategy geared for rapid reproduction in the absence of natural regulating mechanisms, effective management can be so difficult that practitioners of crop protection will, more often than not, result to a broad spectrum, hard chemical control strategy that requires very little management finesse.

There are, however, alternatives to chemical strategies. The use of B.t. is just such an alternative. B.t., with its relative narrow spectrum, in a very much removed from chemical approaches and must be evaluated from an entirely different perspective. The perspective is one of comprehension. With chemical means, the only measurement of effectiveness is acute substraction; a simple and non-complicated strategy. The evaluation of B.t., on the other hand, is an ecological phenomenon, replete with integrations and relations. The practical evaluation of successful B.t. use must take on a quality of omniscience. Many more parameters take on pivotal importance. For Instance, with chemical control in place, there is no need to predict the effectiveness of the infield populations of predators and parasites as moderating factors of Heliothis spp. populations. National enemies are just one of the many other parameters that must be observed when utilizing B.t. (or any other specific compound).