Document Type

Thesis - University Access Only

Award Date

2001

Degree Name

Master of Science (MS)

Department / School

Plant Science

Abstract

The effect of a Semiochemical based insecticide (SLAM®), was evaluated on soil surface dwelling beneficial arthropods at Brookings and Clinton Co., in South Dakota and Iowa respectively. The management area for both locations involved a 16 square mile control core, subjected to aerial applications with SLAM®. Collection of beneficial arthropods was undertaken using pitfall jars following a week before, a week after and 4 weeks after treatment. A generalized linear model (GLM) was used for statistical analysis using the PROC GENMODE and PROC CATMOD in SAS®. For South Dakota 1997, a 27.48% and 53.95% decline in spider populations was observed following 1 week and 4 week sampling in SLAM® plots. In Iowa for the same year, spiders collected at 1 week post treatment with SLAM® showed an increase of over 4.96 times against populations in conventional plots. However spiders at final sampling dates exceeded those in treated fields by 37.2 %. For 1998, spiders showed a consistent rise in SLAM® treated plots for both locations. Scavenging by Wolf spiders (Lycosidae) may account for the increase in spiders for plots treated with the Semiochemical. Decrease in parasites such as Braconidae and Pteromalidae was probably influenced by loss in prey density following SLAM® application. For South Dakota 1997, Carabidae populations did not vary significantly at 1 week post application for treated and conventional plots. However 4 week post count numbers in conventional plots exceeded that of SLAM® by 84.55%. For Iowa 1997 a positive increase in beetle populations was observed following 1 week post treatment with SLAM®. In South Dakota 1998 beetle populations increased in SLAM® fields after 1 week arid 4 week application. However beetle numbers declined in treated plots in Iowa due to flooding caused by heavy rainfall. The genera Evathrus representing (34.4 % arid 48.29%), Harpalus (63.79% and 86.24 % ) arid Pterostichus (21.13 % and 46.30 % ) of the total beetle species, were most abundarit for South Dakota in 1997 and 1998 respectively. Similarly for Iowa the genera Evathrus comprised 63 .10 % of the total beetle species in 1997 arid 85. 5 3 % of the beetle species in 1998. Likewise the genera Harpalus comprised 83.93 % and 94.84 %, and finally beetles belonging to the genera Pterostichus made up for 79.34 % and 12.50 % of the total Carabidae species in 1997 and 1998. The lack of prey accompanied by rainfall events in treated plots, might be a contributing factor to decline in beetle species at South Dakota arid Iowa. Only Pterostichus lucublandus Say, was seen sensitive to SLAM® treatments at South Dakota and Iowa locations in 1997. The ant species Lasius neoniger Emery, was most common and accounted for 60. 71 % and 72. l O % of ant species captured in South Dakota during 1997 and 1998. The corresponding values for Iowa 1997 and 1998 were 69. 70 % and 53.60 %. Formicidae families and species showed an increase across treatment dates and states. A greater than 7.8 fold increase was observed for Staphylinidae for South Dakota 1997, at 4 week post count versus 1 week post. These beetle populations rose in SLAM® plots for 1998 growing season. Specifically 1049 beetles were observed at 1 week post SLAM® application compared to 609 in conventional plots. This behavior is related to the scavenging nature of Staphylinidae. The species Platystethus americanus Erichson, accounted for 73 .10 % of the total number of total species captured. Other beneficial families collected included Coccinellidae and Ichneumonidae. However they were < 1 % of the total beneficial families identified.

Library of Congress Subject Headings

Beneficial insects -- South Dakota
Beneficial insects -- Iowa
Semiochemicals -- Physiological effect
Arthropoda -- Effect of insecticides on -- South Dakota
Arthropoda -- Effect of insecticides on -- Iowa

Format

application/pdf

Number of Pages

151

Publisher

South Dakota State University

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