Introduction Insect pests cause economically significant damage to nursery crops In NC, the green industry reported annual losses of $91,000,000 due to insects and diseases NCDA. 2005. North Carolina green industry economic impact survey.Photo credit Bambara and Baker - via Bugwood
Introduction Insecticides can be useful in managing pest problems. Insecticides can: – Harm natural enemies – Exacerbate secondary pest populations Cloyd, R. 2009. Pesticide use in ornamental plants: what are the benefits? Pest Management Science. 65:345-350 x
Data & Image Credit: Frank, S. and C. Sadof. J. Econ. Entomol. 104(6): 1960‹1968 (2011); DOI: http://dx.doi.org/10.1603/EC11124 50% more natural enemies and 50% fewer spider mites with spray wand than airblast sprayer Introduction
Imidacloprid caused outbreaks of an obscure spider mite on elm trees in NYC Szczepaniec, A., S. F. Creary, K. L. Laskowski, J. P. Nyrop, and M. J. Raupp. 2011. Neonicotinoid insecticide imidacloprid causes outbreaks of spider mites on elm trees in urban landscapes. PLoS ONE 6(5): e20018. doi:10.1371/journal.pone.0020018. Introduction
Lab expts, predators of T. schoenei were poisoned through ingestion of prey exposed to imidacloprid Szczepaniec, A., S. F. Creary, K. L. Laskowski, J. P. Nyrop, and M. J. Raupp. 2011. Neonicotinoid insecticide imidacloprid causes outbreaks of spider mites on elm trees in urban landscapes. PLoS ONE 6(5): e20018. doi:10.1371/journal.pone.0020018. Introduction
Imidacloprid’s tendency to elevate reproduction of T. schoenei also contributed to their elevated densities on treated elms Szczepaniec, A., S. F. Creary, K. L. Laskowski, J. P. Nyrop, and M. J. Raupp. 2011. Neonicotinoid insecticide imidacloprid causes outbreaks of spider mites on elm trees in urban landscapes. PLoS ONE 6(5): e20018. doi:10.1371/journal.pone.0020018. Introduction
3 cover sprays/year for 4+ years had greater scale species diversity and more likely to be scale infested than shorter treatment Raupp et al.: Effects of Cover Sprays and Residual Pesticides. Journal of Arboriculture 27(4): July 2001 Introduction
Insecticides can negatively affect natural enemies Growers tell us scale pests are a relevant problem in the nursery trade – More than previously?? Adkins, C., G. Armel, M. Chappell, J.C. Chong, S. Frank, A. Fulcher, F. Hale, K. Ivors, W. Klingeman III, A. LeBude, J. Neal, A. Senesac, S. White, A. Windham. 2010. Pest Management Strategic Plan for Container and Field-Produced Nursery Crops in GA, KY, NC, SC, TN. A. Fulcher, ed. Southern Region IPM Center.
Scales as Pests of Woody Plants Strikes against us: – Generalists – Thousands of eggs – Wind blown – Difficult to see (small) – Neighboring property can infest and re-infest – Can unknowingly sell infested trees.
Objectives Investigate the effects of systemic & contact insecticides on natural enemies to direct contact with insecticide residue – a worst-case exposure scenario Determine if systemic insecticides offer a more sustainable insecticide choice
Materials and Methods Marathon II, Safari, Sevin, Talstar, water Sprayed on tuliptree Conducted two experiments: – Lab – Field
Lab Materials and Methods 3 leaves from each tree 10 insects /arena, CHO supply – Minute Pirate Bug, Lady beetle, and Lacewing
8 replicate arena/trt Assessed survival every 24 h for 4 d Removed dead daily Lab Materials and Methods
Field Materials and Methods Attached three arenas to each tree (one species per arena) – Lady beetle, Minute Pirate Bug, Aphidius
Field Materials and Methods Installed pitfall trap at base of each tree Every 48 h – Assessed survival – Replaced 10 new insects
Lacewing, Minute Pirate Bug, Lady Beetle Lady beetle Minute Pirate Bug Lacewing
Minute Pirate Bug Survival 96 h after Applications
Conclusions Limited study Worst case scenario Insecticide effect on beneficial insect varies with insect species, pesticide, and times after application Sevin and Talstar appear to be most toxic Minute Pirate Bug most affected Safari appears to have the least negative effect
Implications on Pest Mgt Augmentative Biological Control Where to release Plant density influence natural enemy survival
Hydrangea Spray Penetration Dense canopy – Droplet density was reduced from 56 deposits/cm 2 on the exterior position to 2 deposits/cm 2 on the middle and interior positions 96% loss
Hydrangea Spray Penetration Sparse canopy – Received 463% more coverage in the middle of the canopy than the dense plants Regardless of density, the interior received less than 1% coverage!
Beneficial Insect Survival Only the interior and middle positions of dense plants protected greater than 50% of the lady beetles Only the interior position of dense plants protected greater than 50% of lacewings over the course of the experiment If not lethal to natural enemies perhaps not lethal to pest insects!
Intelligent Spray Systems Automatic controllers – Computer program – Signal generation and amplification unit – Pulse width modulated solenoid valves – Algorithm Ultrasonic sensor Laser sensor
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