This document is EENY-129, one of a series of Featured Creatures from the Entomology and Nematolo... more This document is EENY-129, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: April 2000. Revised: November 2002. https://edis.ifas.ufl.edu/in286
Journal of the American Society for Horticultural Science, 2001
Squash silverleaf (SSL) is a physiological disorder of vegetables in the genus Cucurbita L. cause... more Squash silverleaf (SSL) is a physiological disorder of vegetables in the genus Cucurbita L. caused by feeding of nymphs of the silverleaf whitefly (SLW) (Bemisia argentifolii Bellows & Perring). SSL causes a silvering of the leaves and a blanching of fruit. Leaf silvering is caused by developmental separation of the upper epidermis and the palisade mesophyll layer resulting in additional air space and altered light reflection. The anatomical development of SSL was analyzed in young leaves of zucchini squash (Cucurbita pepo L.) using two susceptible genotypes (`Elite' and YSN347-PMR) and two tolerant genotypes (ZUC76-SLR and ZUC33-SLR/PMR). SLW nymphs were allowed to feed only on the mature leaves and the anatomy of the developing leaves was observed by light microscopy and transmission electron microscopy. Silvering began at the apex of young leaves and developed basipetally. The increased percentage of air space that resulted between the upper epidermis and palisade layers was ...
Abstract St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, is used as lawn grass throug... more Abstract St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, is used as lawn grass throughout the southern United States for its wide adaptation to varying environmental conditions. The southern chinch bug, Blissus insularis Barber, is the plant's most damaging insect pest. Host plant resistance of St. Augustinegrass has been determined in numerous studies using various techniques. However, efficacy of these various procedures in determining St. Augustinegrass resistance to southern chinch bug has not been determined. The objective of this study was to determine the effect of time and methodologies in assesing St. Augustinegrass resistance to southern chinch bugs. Four varieties were tested for resistance using 4 methods (bag, jar, box, tube) and 5 time intervals to measure chinch bug mortality. Overall, survival was greater in whole-plant methods (box and tube) than excised stolon methods (bag and jar). The bag test gave the most erratic results of the 4 methods. The effect of time in determining resistance was also evident. In our tests, it was clear that shorter time intervals in measuring mortality may result in not measuring resistance in a variety. In summary, researchers should carefully consider method, time and temperature as important variables in determining St. Augustinegrass resistance to southern chinch bugs.
Southern chinch bug, Blissus insularis Barber, is a severe pest of St. Augustinegrass throughout ... more Southern chinch bug, Blissus insularis Barber, is a severe pest of St. Augustinegrass throughout the southern United States. Host plant resistance is an environmentally friendly method to manage chinch bug infestations and is increasingly important, as the southern chinch bug develops resistance to insecticides. In this study, in an effort to understand resistance mechanisms in two varieties of St. Augustinegrass ('FX-10' and 'NUF-76'), we used the electrical penetration graph method to quantify stylet probing behaviors in two resistant and two susceptible St. Augustinegrass varieties. Overall, chinch bugs spent less time probing on resistant FX-10 and NUF-76 than on susceptible 'Floratam' and 'Palmetto', and individual probes were shorter in average duration but more numerous in resistant varieties than in susceptible varieties. During probing, chinch bugs spent more time in pathway-associated stylet activities (i.e., penetration through epidermal an...
Resistance in lettuce, Lactuca sativa L., to feeding by adult banded cucumber beetle, Diabrotica ... more Resistance in lettuce, Lactuca sativa L., to feeding by adult banded cucumber beetle, Diabrotica balteata (LeConte), was evaluated using three screening methods: leaf disks, excised leaves and intact leaves attached to plants. Dual-choice and no-choice bioassays were used to evaluate each method based on leaf area consumption. Methods of testing had a significant effect on the level of feeding damage by D. balteata on two lettuce cultivars, Tall Guzmaine and Valmaine. Valmaine expressed a significant degree of resistance to D. balteata damage when intact leaf and excised leaf methods were used in dual-choice bioassays between Tall Guzmaine and Valmaine, but the latter failed to show resistant characteristics in no-choice tests when excised leaves were used. Furthermore, there was no significant difference in D. balteata feeding between Tall Guzmaine and Valmaine in the leaf disk tests. Therefore, whole plants are the best method to evaluate lettuce cultivars for resistance to D. bal...
Annals of the Entomological Society of America, 2013
Electrical penetration graph (EPG) monitoring has been used extensively to elucidate mechanisms o... more Electrical penetration graph (EPG) monitoring has been used extensively to elucidate mechanisms of resistance in plants to insect herbivores with piercing-sucking mouthparts. Characterization of waveforms produced by insects during stylet probing is essential to the application of this technology. In the studies described herein, a four-channel Backus and Bennett AC-DC monitor was used to characterize EPG waveforms produced by adults of two economically important chinch bug species: southern chinch bug, Blissus insuhris Barber, feeding on St. Augustinegrass, and western chinch bug, Blissus occiduus Barber, feeding on buffalograss. This is only the third time a heteropteran species has been recorded by using EPG; it is also the first recording of adult heteropterans, and the first of Blissidae. Probing of chinch bugs was recorded with either AC or DC applied voltage, no applied voltage, or voltage switched between AC and DC mid-recording, at input impedances ranging from 106 to 1010 ...
This document is EENY-129, one of a series of Featured Creatures from the Entomology and Nematolo... more This document is EENY-129, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: April 2000. Revised: November 2002. https://edis.ifas.ufl.edu/in286
Journal of the American Society for Horticultural Science, 2001
Squash silverleaf (SSL) is a physiological disorder of vegetables in the genus Cucurbita L. cause... more Squash silverleaf (SSL) is a physiological disorder of vegetables in the genus Cucurbita L. caused by feeding of nymphs of the silverleaf whitefly (SLW) (Bemisia argentifolii Bellows & Perring). SSL causes a silvering of the leaves and a blanching of fruit. Leaf silvering is caused by developmental separation of the upper epidermis and the palisade mesophyll layer resulting in additional air space and altered light reflection. The anatomical development of SSL was analyzed in young leaves of zucchini squash (Cucurbita pepo L.) using two susceptible genotypes (`Elite' and YSN347-PMR) and two tolerant genotypes (ZUC76-SLR and ZUC33-SLR/PMR). SLW nymphs were allowed to feed only on the mature leaves and the anatomy of the developing leaves was observed by light microscopy and transmission electron microscopy. Silvering began at the apex of young leaves and developed basipetally. The increased percentage of air space that resulted between the upper epidermis and palisade layers was ...
Abstract St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, is used as lawn grass throug... more Abstract St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze, is used as lawn grass throughout the southern United States for its wide adaptation to varying environmental conditions. The southern chinch bug, Blissus insularis Barber, is the plant's most damaging insect pest. Host plant resistance of St. Augustinegrass has been determined in numerous studies using various techniques. However, efficacy of these various procedures in determining St. Augustinegrass resistance to southern chinch bug has not been determined. The objective of this study was to determine the effect of time and methodologies in assesing St. Augustinegrass resistance to southern chinch bugs. Four varieties were tested for resistance using 4 methods (bag, jar, box, tube) and 5 time intervals to measure chinch bug mortality. Overall, survival was greater in whole-plant methods (box and tube) than excised stolon methods (bag and jar). The bag test gave the most erratic results of the 4 methods. The effect of time in determining resistance was also evident. In our tests, it was clear that shorter time intervals in measuring mortality may result in not measuring resistance in a variety. In summary, researchers should carefully consider method, time and temperature as important variables in determining St. Augustinegrass resistance to southern chinch bugs.
Southern chinch bug, Blissus insularis Barber, is a severe pest of St. Augustinegrass throughout ... more Southern chinch bug, Blissus insularis Barber, is a severe pest of St. Augustinegrass throughout the southern United States. Host plant resistance is an environmentally friendly method to manage chinch bug infestations and is increasingly important, as the southern chinch bug develops resistance to insecticides. In this study, in an effort to understand resistance mechanisms in two varieties of St. Augustinegrass ('FX-10' and 'NUF-76'), we used the electrical penetration graph method to quantify stylet probing behaviors in two resistant and two susceptible St. Augustinegrass varieties. Overall, chinch bugs spent less time probing on resistant FX-10 and NUF-76 than on susceptible 'Floratam' and 'Palmetto', and individual probes were shorter in average duration but more numerous in resistant varieties than in susceptible varieties. During probing, chinch bugs spent more time in pathway-associated stylet activities (i.e., penetration through epidermal an...
Resistance in lettuce, Lactuca sativa L., to feeding by adult banded cucumber beetle, Diabrotica ... more Resistance in lettuce, Lactuca sativa L., to feeding by adult banded cucumber beetle, Diabrotica balteata (LeConte), was evaluated using three screening methods: leaf disks, excised leaves and intact leaves attached to plants. Dual-choice and no-choice bioassays were used to evaluate each method based on leaf area consumption. Methods of testing had a significant effect on the level of feeding damage by D. balteata on two lettuce cultivars, Tall Guzmaine and Valmaine. Valmaine expressed a significant degree of resistance to D. balteata damage when intact leaf and excised leaf methods were used in dual-choice bioassays between Tall Guzmaine and Valmaine, but the latter failed to show resistant characteristics in no-choice tests when excised leaves were used. Furthermore, there was no significant difference in D. balteata feeding between Tall Guzmaine and Valmaine in the leaf disk tests. Therefore, whole plants are the best method to evaluate lettuce cultivars for resistance to D. bal...
Annals of the Entomological Society of America, 2013
Electrical penetration graph (EPG) monitoring has been used extensively to elucidate mechanisms o... more Electrical penetration graph (EPG) monitoring has been used extensively to elucidate mechanisms of resistance in plants to insect herbivores with piercing-sucking mouthparts. Characterization of waveforms produced by insects during stylet probing is essential to the application of this technology. In the studies described herein, a four-channel Backus and Bennett AC-DC monitor was used to characterize EPG waveforms produced by adults of two economically important chinch bug species: southern chinch bug, Blissus insuhris Barber, feeding on St. Augustinegrass, and western chinch bug, Blissus occiduus Barber, feeding on buffalograss. This is only the third time a heteropteran species has been recorded by using EPG; it is also the first recording of adult heteropterans, and the first of Blissidae. Probing of chinch bugs was recorded with either AC or DC applied voltage, no applied voltage, or voltage switched between AC and DC mid-recording, at input impedances ranging from 106 to 1010 ...
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