From insecticides to biological control of pests in sugarcane: an experience of half a century in Venezuela

Abstract

Biological control has been established as a unique measure for managing borers of the genus Diatraea and the candelilla Aeneolamia spp., both of which are key pests of sugarcane in Venezuela. Optimal results have been achieved with the use of parasitoids and entomopathogens. Systematic releases of the Amazonian fly Lydella minense from the mid-20th century and the establishment of the braconid wasp Cotesia flavipes from 1987 led to effective control of borers. In the case of Aeneolamia varia, a pest formerly controlled with frequent insecticide applications, an efficient solution was the introduction of the entomopathogenic fungus Metarhizium anisopliae in 1977. This measure has been established as efficient in controlling adult Aeneolamia, though nymphs were less controlled. This issue was effectively addressed in 2004 with the introduction of the entomopathogenic nematode Heterorhabditis bacteriophora, which has been widely used as a biological measure to avoid the application of insecticides. To illustrate this, we can consider the case of Azucarera Río Turbio. Despite experiencing a reduction in cultivated areas in recent harvests due to various factors, this establishment has witnessed a significant decline in Diatraea infestations over the past 58 years. Infestation rates have decreased from 15% to 3.18%, resulting in a saving of 170,552.62 metric tons valued at USD 49,196,045. The cost of implementing biological control measures amounts to USD 1,187,189, translating into a favorable benefit-cost ratio of USD 41.44. Before the adoption of biological control methods, Aeneolamia infestations were exclusively controlled using chemical insecticides applied to both the foliage for adults and the soil for nymphs. Concurrently, since then, entomopathogenic fungus M. anisopliae, produced by national companies, has been deployed across 87,000 hectares between 1986 and 1990. Moreover, since 2004, the use of entomopathogenic nematodes to control Aeneolamia nymphs has been integrated into pest management practices.