Field experiments for the chemical control of the pickleworm (Diaphania nitidalis), the melonworm (D. hyalinata), the leafminer (Liriomyza sativae), and nematodes (Meloidogyne incognita and Rotylenchulus reniformis) on cucumber cultivar Ashley were established in two locations in Puerto Rico in 1979 and 1980. In the second test, a lower number of mined leaves was observed on methamidophos-treated plots as well as a significant lower index of leafminer damage. All chemicals controlled the pickleworm effectively. Highest yields were obtained from plots treated with the highest dosage of acephate and with the intermediate dose of methamidophos. Applications of carbofuran, acephate, methomyl and permethrin reduced the melonworm damage in the third test. Highest yields were obtained from carbofuran-treated plots. All nematicides controlled nematodes in the soil.