1. RESPONSE OF CHILLI THRIPS, SCIRTOTHRIPS DORSALIS TO SOME SELECTIVE INSECTICIDES
Dakshina R. Seal, Vivek K. Jha, and Garima kakkar; University of Florida-IFAS, Tropical Research and Education Center
Abstract
The chilli thrips, Scirtothrips dorsalis Hood is a significant pests of various vegetable, tropical fruit and ornamental crops. We evaluated neonicotinoid (imidacloprid, thiamethoxam and acetamiprid) and anthranilamid (rynaxypyr and cyazypyr) insecticides for the control of this pest on `Jalapeno’ pepper, Capsicum annuum L, in Homestead, FL. Imidacloprid and thiamethoxam significantly controlled adults and larvae of chilli thrips. Spinosad and acephate provided similar level of control of chilli thrips as the neonicotinoid insecticides. Rynaxypyr and cyazypyr provided inconsistent control chilli thrips in various studies. Voliam Flexi and Durivo significantly reduced chilli thrips.
Introduction
Scirtothrips dorsalis Hood is an important pests of various vegetable, ornamental and fruit crops in southern and eastern Asia, Africa, and Oceania (Ananthakrishnan 1993, CABI/EPPO 1997, CAB 2003). Plants in 112 taxa are reported to be the hosts of S. dorsalis. One or more S. dorsalis life stages occur on all above-the-ground plant parts of its hosts, and causes scarring damage due to its feeding (Chang et al. 1995).
The Florida Nurserymen and Growers Association considers S. dorsalis as one of the thirteen most dangerous exotic pest threats to the industry (FNGA 2003). Venette and Davis (2004) projected the potential geographic distribution of S. dorsalis in North America to extend from southern Florida to north of the Canadian boundary, as well as to Puerto Rico and the entire Caribbean region. This suggests that this pest could also become widely established in South America and Central America. S. dorsalis is a vector of various viral and bacterial diseases (Amin et al. 1981; Mound and Palmer 1981; Ananthakrishnan 1993).
Here we report on the effectiveness of neonicotinoid and anthranilamid insecticides against chilli thrips. Elsewhere we reported effectiveness of various other insecticides in controlling chilli thrips (Seal et al. 2006).
Results and Discussion
Both thiamethoxam and imidacloprid applied on the foliage were effective as spinosad in controlling chilli thrips adults on `Jalapeno’pepper when compared with the nontreated control (Fig. 1). Both neonicotinoid insecticides (thiamethoxam and imidacloprid) were also effective in controlling chilli thrips larvae (Fig. 2). The performance of thiamethoxam and imidacloprid
Rynaxypyr and cyazypy, applied on the foliage, did not significantly reduced chilli thrips (Fig.3). Voliam Xpress performance was inconsistent in the present studies in controlling chilli thrips. Voliam flexi and Durivo significantly reduced chilli thrips population on `Jalapeno’ pepper when compared with the nontreated control.
In the third study, acephate, acetamiprid and premix product of imidacloprd and cyfluthrin provided significant control of chilli thrips adults and larvae when compared with the nontreated control (Fig. 4). In this study, cyazypyr equaled the above insecticides in controlling chilli thrips. Novaluron and spirotetramet also reduced chilli thrips.
Materials and Methods
Three studies were conducted to determine effectiveness of various insecticides in managing chilli thrips. In all studies treatments were applied on the foliage of `Jalapeno’ pepper plants.
In the first study, thiamethoxam (8 oz/acre; Actara® 20 WG; Syngenta Cropprotection) and imidacloprid (3.75 oz/acre; Provado® 1.6F; Bayer Cropscience), two neonicotinoid insecticides were evaluated against chilli thrips using `Jalapeno’ pepper in a greenhouse. These two insecticides were compared with spinosad (7.0 oz/acre) and a nontreated control. All treatments were applied on four dates at weekly intervals.
The second study was conducted to evaluate effectiveness of anthranilamid insecticides (rynaxypyr and cyazypr) alone or in combination with other insecticides as a premix (Voliam flexi,: rynaxypyr + Actara; Voliam Xpress: rynaxypyr + Warrior; Durivo: rynaxypyr + Platinum) against chilli thrips in a greenhouse. Treatments were applied on the foliage. All treatments were applied on four dates at weekly intervals.
The third study was conducted in a field condition using `Jalapeno’ pepper. Treatments used in this study were: spinetoram (8.0 oz/acre, Radiant SC); acephate (8.16 oz/acre, Orthene 97); acetamiprid (4.0 oz, Assail 30 SG); novaluron (12.0 oz/acre, Rimon 0.83 EC); spirotetramat (5.0 oz/acre, Movento); imidacloprid in combination with cyfluthrin (5.0 oz/acre, Leverage 2.7) and a nontreated control. All insecticide treatments were applied on the foliage at weekly intervals for four weeks. .
Conclusions
Neonicotinoid insecticides like spinetoram provided significant reduction of S. dorsalis. Voliam flexi and Durivo also provided satisfactory reduction of S. dorsalis. These insecticides can be used in rotation with acephate and cyazypyr in managing chilli thrips.
P > 0.05
Figure 3. Mean numbers of chilli thrips
on pepper plants treated with anthranilamid insecticides.
Figure 4. Mean numbers of chilli thrips
on pepper plants treated with various insecticides.
Figure 1. Chilli thrips adults on treated
pepper plants on subsequent days after
application of neonicotinoid insecticides.
Figure 2. Chilli thrips larvae on treated
pepper plants on subsequent days after
application of neonicotinoid insecticides.
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