Impact of low release rates of the assassin bug Pristhesancus plagipennis (Walker) (Hemiptera: Reduviidae) on Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton

Abstract

A challenge with the inundative release of beneficial insects in pest management programs is to achieve a viable balance between predator release rates and biological control efficacy. This paper examines postrelease survival and biological control efficacy of the assassin bug, Pristhesancus plagipennis (Walker) released in cotton at rates of 1.0, 0.75, 0.5 and 0.25 nymphs per metre crop row. These releases resulted in > 72% survival of nymphs with respective field populations of 0.75, 0.54, 0.41 and 0.25 nymphs m -1 4 weeks postrelease. Each of the P. plagipennis nymph release treatments gave significant reductions in Helicoverpa spp. larval densities, whilst only the higher nymph release rates of 1.0 and 0.75 m -1 decreased densities of mirids, Creontiades spp. The data suggest that release rates of P. plagipennis at or below 1.0 nymph m -1 aid postrelease survival and provide significant reductions in numbers of some cotton pest insects.

Bioefficacy of Rhynocoris longifrons (Stål) (Heteroptera: Reduviidae) against multiple cotton pests under screen house and field conditions

“…In fact, it is known that P. solenopsis 45 Comparatively of the cotton production (1585 kg/ha) at Tamil Nadu of India, the yield recorded during our study in cotton fields during south-west monsoon (2068 kg/ha) and post-monsoon season (1862 kg/ha) reveal that release of reduviids reduced impact of insect pests thus enhance cotton production. Similar trends were also observed when P. plagipennis was release in cotton fields 17,39 . Although the cost benefit ratio was low (1:1.28 or 1:1.24) comparatively to entomopathogenic insecticides such as HaNPV (1:3.50) or Bt (1:1.23) used for cotton protection 47,48 , it had been higher than those of control highlighting the benefit of integrating this predator in cotton pest management.…”

“…The first release of this predator in cotton fields was capable to reduce A. gossypii and P. solenopsis populations during south-west and post monsoon compared with the control. Similarly, the field release of some reduviid predators such as Pristhesancus plagipennis Walker 17,39 , Platymeris laevicollis Distant 40 and Rhynocoris marginatus (Fab.) 19,20 were successful in reducing various pests in coconut palm, cotton and groundnut fields.…”

Mass rearing and augmentative biological control evaluation of Rhynocoris fuscipes (Hemiptera: Reduviidae) against multiple pests of cotton

“…Several studies have long evaluated the role of natural enemies for control of cotton insect pests; , however, very few of these studies have assessed the use of predatory reduviid bugs against these pests under field conditions . Although augmentative release of predators, especially reduviids, is a major component in BIPM systems, there is limited information available about its efficacy in the literature. Hence, the present study is considered to be important for biological control using reduviid predators.…”

“…In other similar studies, field releases of P. plagipennis and R. marginatus were successful in reducing S . litura, H. armigera and A. craccivora populations in cotton and groundnut fields . However, there are no reports available concerning the utilization of an augmentative release of R. fuscipes for cotton pest management.…”

From lynx spiders to cotton: Behaviourally mediated predator effects over four trophic levels

“…Mirid densities had a variable effect on boll damage.This indicates that you can manage a pest without managing the damage it causes. Often the effectiveness of a biological control method is measured by the extent to which it reduces the target pest population (Grundy 2004). Here in the All treatment, the numbers of mirids have been reduced (compared to the Mirid only treatment) but the damage has not, indicating that management of this pest has not been achieved.…”