Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University

Spring 2003 Resistant Pest Management Newsletter Vol. 12, No.2indoxacarb vs 4 coccinellids p.30 plants). The effect ofboth insecticides on the spiders was equivalent toendosulfan (6.5 vs 7 spiders p.30 plants).Effectiveness of spinosad and indoxacarb in mixturewith other insecticides:Data presented in Figures 7a-d showed comparedactivity of spinosad or indoxacarb based associationswith profenofos and acetamiprid, and pyrethroïd basedassociations on cotton bollworms and some suckingpests.The profenofos based association with spinosad orindoxacarb provided an activity level at leastequivalent to cypermethrin-profenofos associationagainst H. armigera (0.3 and 1 vs 1.1 larva p. 30plants, respectively for indoxacarb-profenofos,spinosad-profenofos and cypermethrin-profenofos).The same tendency was observed against the mite P.latus (0.1 and 2.5 vs 2.9 mite infested plants p. 3 rows).The acetamiprid-based association with spinosadwas at least equivalent to the cypermethrin-acétamipridassociation against D. voëlkeri (74.2 vs 90.7 Dysdercusp. 30 plants). This association was much more effectiveagainst D. voelkeri than the indoxacarb-acetamipridassociation (109.3 Dysdercus p. 30 plants). Concerningthe endocarpic bollworm species (C. leucotreta & P.gossypiella) the spinosad-acetamiprid associationshowed an activity level equivalent to thecypermethrin-acetamiprid (4 vs 2 larvae p. 100 bolls)while the activity remained very low for theindoxacarb-acetamiprid association (9.5 larvae p. 100bolls).DISCUSSION The present study pointed out the strengthsand weaknesses of spinosad and indoxacarb withrespect to major insect pests and beneficial species.The activity of spinosad and indoxacarb variedsignificantly according to insect pest species orbeneficial species.The spinosad activity spectrum comprisedexocarpic bollworm species (H. armigera, Earias spp,and D. watersi) and cotton leafworms S. littoralis andA. flava. It appeared to have a certain activity againstthe endocarpic bollworm species (C. leucotreta & P.gossypiella), the jassid J. fascialis, and the mite P.latus. This activity noticed especially on sucking pestssuch as the jassid J. fascialis and the mite P. latus needto be confirmed in more field trials, for the manualpesticide states that spinosad is non toxic to suckingpests. Indeed, spinosad appeared very limited againstthe aphid A. gossypii and the cotton stainer D. voëlkeri.With regard to benefials, spinosad proved safer toCoccinela spp and spiders.79