Paul DeBach

Paul DeBach appears in the book as an entomologist whose observations give biological control both a cautionary history and an economic measure. He describes the consequences of pesticide use against scale insects and estimates that California’s investment in biological control yielded a return many times its cost.

Biological Control and the Scale-Insect Reversal

DeBach, identified as a doctor and associated with the Citrus Experiment Station in Riverside, characterized the rapid return of scale insects after their natural enemies had been disrupted as a possible end of an era. The infestation reappeared quickly, and the resulting damage exceeded anything seen for fifty years. The reversal demonstrates how a treatment that suppresses a pest can also undermine the ecological controls that had kept it in check.

The aftermath made control more complicated rather than more secure. The vedalia beetle could be maintained only through repeated releases and careful attention to spray schedules, limiting its contact with insecticides. Citrus growers also depended on decisions made beyond their own acreage: severe infestations on neighboring land could leave them vulnerable regardless of their own practices. In DeBach’s account, biological control was not a one-time substitute for spraying but a continuing arrangement requiring coordination and protection of beneficial insects.

The Economic Case for Biological Control

The book also cites DeBach’s estimate that California received $100 million in return for a $4 million investment in biological-control work. That comparison presents the approach not merely as an ecological alternative but as a substantial economic success. Elsewhere, biological control is illustrated through natural enemies of pests, including the Tiphia wasp against the Japanese beetle and agents that controlled scale insects and mealybugs; the text attributes California savings of several million dollars a year to such controls.

Together, the estimate and the scale-insect example give DeBach’s role its particular significance. The financial return supports investment in natural enemies, while the resurgence episode shows how easily that investment can be compromised when insecticides damage the organisms doing the controlling. Biological control’s promise therefore depends on sustained care, compatible spray practices, and attention to ecological relations that extend across property lines.