Journal of Economic Entomology (2000) 93, 1779-1787

Carlos J. Pérez, Petrona Alvarado, Cony Narváez, Freddy Miranda, Luis Hernández, Héctor Vanegas, Allan Hruska and Anthony M. Shelton (2000)
Assessment of insecticide resistance in five insect pests attacking field and vegetable crops in Nicaragua
Journal of Economic Entomology 93 (6), 1779-1787
Abstract: Field populations of Hypothenemus hampei (Ferrari), Plutella xylostella (L.), Spodoptera exigua (Hübner), Helicoverpa zea (Boddie), and Bemisia tabaci (Gennadius) were tested for resistance to several insecticides commonly used in Nicaragua. Assays were conducted to estimate the LD₅₀s or LC₅₀s and the corresponding resistance ratios. A diagnostic concentration was used to discriminate between susceptible and resistant strains of H. hampei. The tests with >6,000 H. hampei adults collected from six different sites indicate the absence of resistance to endosulfan. Resistance to cypermethrin, deltamethrin, chlorfluazuron, thiocyclam, and methamidophos was documented in six field populations of P. xylostella. High levels of resistance to cypermethrin and deltamethrin, but moderate levels of resistance to chlorpyriphos and methomyl, were also documented in two field populations of S. exigua. Moderate levels of resistance to cypermethrin, deltamethrin and chlorpyriphos were also documented in three field populations of H. zea. Moderate to high levels of resistance to bifenthrin, methamidophos and endosulfan were documented in four field populations of B. tabaci. The presence of significant correlations between LD₅₀s or LC₅₀s suggests the occurrence of cross-resistance or simultaneous selection for resistance by different insecticides with different modes of action. Our data could not differentiate between these two possibilities. Because insecticides will continue being used in Nicaragua, a resistance management program is urgently needed. The implementation of integrated pest management tactics must be accompanied by specific regulations for pesticide registration. In the future, pesticide registration regulations in Nicaragua should include periodic resistance monitoring. The mechanisms to cover the costs of resistance monitoring and resistance management should also be established.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Anthony M. Shelton, Allan J. Hruska

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plutella xylostella		Nicaragua
	Spodoptera exigua		Nicaragua
	Helicoverpa zea		Nicaragua
	Bemisia tabaci		Nicaragua
	Hypothenemus hampei		Nicaragua