Case studies in cotton and citrus: Use of entomopathogenic nematodes

Based on the case studies examined here and other literature, we can see that most nematode success stories share two basic characteristics: a suitable nematode for the target pest, and favorable crop economics. For example, nematodes associated witb control of Diaprepes abbreviatus (L.), Otiorhynehus sulcatus (L.) and sciarid pests, being highly suited to their hosts, are applied in relatively high value commodities, and face little or no competition from other control measures. In cases where entomopathogenic nematodes have not succeeded, the causes may generally found to be a poor match of nematode and host, or poor economic conditions. For example, Steinernema riobrave proved to be highly efficacious toward Pink bollworm, but in cotton, nematodes could not compete on an economic level witb other control strategies. Other insects in row crops fall into the same category, eg., Helieoverpa zea and Diabrotica spp. in corn. In other instances a suitable match of nematode to target pest could not be found e.g. wireworms (Coleoptera: Elateridae) and imported fire ants, Solenopsis invicta Buren, where strategies to employ entomopathogenic nematodes are futile. Therefore, we conclude that the two most important qualities required for entomopathogenic nematodes to be commercially successful are: host suitability (proper match) of nematode to host, and favorable economic conditions.