Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/17/2012
Publication Date: 5/1/2012
Citation: Kumar, V., Seal, D.R., Kakkar, G., McKenzie, C.L., Osborne, L.S. 2012. Chilli thrips, Scirtothrips dorsalis: A potential threat to cotton production in the USA. Proceedings Beltwide Cotton Conferences, 65th Cotton Insects Research Control Confernce. 2:817-819. Interpretive Summary: The chilli thrips, Scirtothrips dorsalis Hood is an emerging pest of many economically important vegetable and ornamental crops grown in the United States. Since its advent to Florida in 2005, this pest has rapidly dispersed across the state and is causing significant damage to horticultural and nursery production statewide. Detection of S. dorsalis larvae and adults in fresh vegetation is very difficult due to their thigmotactic behavior and tiny stature (< 2mm in length). Studies were conducted to assess its host preference, abundance and distribution pattern to evaluate its damage potential on the hosts understudy. In the choice host preference test, cotton was found to be preferred over pepper and peanut. Results from the age specific abundance and within plant distribution showed high infestation of S. dorsalis on the young plants and leaves, suggesting that control measures should be adopted at the initiation of infestation during early stage of cotton plantings. Abundance of S. dorsalis was found year round on the cotton but infestation was significantly higher in July and August than rest of the months. Based on the results from our current and previous studies it can be concluded that cotton is an important feeding and reproductive host of S. dorsalis and this pest is capable of posing a serious threat to cotton production in this region.
Technical Abstract: Several greenhouse studies including host preference, age specific abundance, within plant distribution and seasonal abundance of a newly introduced thrips pest, Scirtothrips dorsalis Hood, were conducted to evaluate its pest status on cotton. Cotton was found to be the most preferred host among the three hosts (cotton, pepper, and peanut) evaluated. Highest abundance of S. dorsalis was reported on 1-5 week old cotton plants with a maximum damage rating of 3.8 out of 5. Study on within plant distribution suggested abundance of S. dorsalis was significantly higher on top young leaves of cotton compared to middle and basal leaves. Significantly higher abundance of S. dorsalis larvae and adults were reported in the months of July and August than other times of the year. Our results suggest that this pest could pose as a threat to cotton production in the United States.