scholarly journals Getting Mixed-Up: Are Greenhouse Producers Adopting Appropriate Pesticide Mixtures to Manage Arthropod Pests?

2009 ◽  
Vol 19 (3) ◽  
pp. 638-646 ◽  
Author(s):  
Raymond A. Cloyd

Pesticide mixtures are commonly used by greenhouse producers to deal with the array of arthropod (insect and mite) pests encountered in greenhouses. Greenhouse producers tank mix pesticides due to convenience because it is less time consuming, costly, and labor intensive to mix together two or more pesticides into a single spray solution and then perform one spray application compared with making multiple applications. Pesticide mixtures may also result in improved arthropod pest control. However, there has been no quantitative assessment to determine what pesticide mixtures (two-, three-, and four-way combinations) are being adopted by greenhouse producers and why. As such, a survey was conducted by distributing evaluation forms in conjunction with three sessions at two greenhouse producer conferences (two in 2007 and one in 2008) to obtain data on the types of pesticide mixtures used by greenhouse producers and determine if there are any problems associated with these pesticide mixtures. The evaluation form requested that participants provide information on the four most common pesticide mixtures (insecticides and/or miticides) used and for what specific arthropod pests. The response rate of the evaluation forms was 22.5% (45/200). The two-way pesticide mixture that was cited most often (n = 8) was the abamectin (Avid) and bifenthrin (Talstar) combination. The two pesticides typically included in a majority of the two-way and three-way mixtures were spinosad (Conserve) and abamectin. Spinosad was a component of 17 two-way and 7 three-way combinations, while abamectin was cited in 15 two-way and 9 three-way combinations. Both products are labeled for control of the western flower thrips (Frankliniella occidentalis), which is one of the most important insect pests in greenhouses. One pesticide mixture that was difficult to interpret involved the fungicides, thiophanate-methyl (Cleary's 3336) and metalaxyl (Subdue). This mixture was cited twice, and the arthropod pest listed was thrips (Thysanoptera). However, both fungicides have no insecticidal activity. Two of the mixtures listed in the survey used pesticides with similar modes of action: acephate (Orthene) + methiocarb (Mesurol), and pyrethrins (Pyreth-It) + bifenthrin (Talstar). A number of the pesticide mixtures listed for spider mites (Tetranychidae) were questionable due to similar life stage activity of the a.i. as indicated on the label including fenpyroximate (Akari) + clofentezine (Ovation), abamectin + chlorfenapyr (Pylon), and bifenazate (Floramite) + etoxazole (TetraSan). In fact, 38% of pesticide mixtures cited for twospotted spider mite (Tetranychus urticae) control should have been avoided due to analogous life stage activity. The data obtained from the survey clearly demonstrates that greenhouse producers implement a wide-range of pesticide mixtures to deal with the multitude of arthropod pests in greenhouses. However, the basis by which greenhouse producers decide the types of pesticides to mix together is not known. As such, the survey data can be used to direct future multistate or multiregional extension (outreach) efforts in developing programs specifically designed to educate greenhouse producers on which pesticides should and should not be mixed together.

2020 ◽  
Vol 55 (3) ◽  
pp. 350-365
Author(s):  
Yinping Li ◽  
Raymond A. Cloyd ◽  
Nora M. Bello

Abstract The rove beetle, Dalotia coriaria (Kraatz) (Coleoptera: Staphylinidae), is a soil-dwelling predator that preys upon insect pests residing in growing media. Minimal information exists addressing its predation on western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), below-ground life stages. Two laboratory experiments were conducted to assess the effects of western flower thrips pupal stage, predator–prey ratio, and searchable area on predation efficacy of rove beetle adults. In Experiment 1, predation was recorded in response to two thrips pupal stages (prepupae and pupae); three predator–prey ratios (1:5, 1:10, 1:15) and predator–prey ratios that were 2, 3, and 4 times greater. Experiment 2 was designed to assess predation in response to those predator–prey ratios along with searchable areas in 15.2- and 11.5-cm-diameter containers. Response was measured by capturing thrips adults on yellow sticky cards (YSC) as they emerged from pupation. The estimated mean probability of thrips adults captured on the cards was significantly higher for the 1:5 (61.1%) than for the 1:10 (39%) and 1:15 (34.7%) predator–prey ratios. The estimated mean probability of thrips adults captured on the cards for 2 times the predator–prey ratio (57%) was significantly higher than 3 times (37.2%) and 4 times (40.6%) the ratios. A significantly higher estimated mean probability of thrips adults was captured on the cards in the 15.2-cm-diameter containers than in the 11.5-cm-diameter containers. We conclude that a predator–prey ratio of 1:15 would result in fewer rove beetle adults needed to reduce western flower thrips prepupae/pupae stages and subsequent adult populations.


Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1910
Author(s):  
Zhijian Zhang ◽  
Changying Zheng ◽  
Nemat O. Keyhani ◽  
Yulin Gao ◽  
Junping Wang

The western flower thrips, Frankliniella occidentalis, is an aggressive agricultural insect pest causing significant damage to a wide range of fruit, vegetable, and ornamental crops. Beauveria bassiana is a broad-host-range entomopathogenic fungus capable of infecting and killing F. occidentalis. Infection of thrips by B. bassiana strain BbYT12 using a concentration of 1 × 108 conidia/mL resulted in 81.48% mortality in adults in 6 d (LT50 = 90 ± 15.1 h). Scanning electron microscopy of the infection process revealed preferential adhesion and germination of fungal spores to inter-segmental folds or grooves on the insect body surface with penetrating germlings and extended hyphae visualized during the initial stages of infection (6–24 h). Histological analyses showed the appearance of in vivo hyphal bodies in sagittal sections and the fat body as early as 24 h post-infection. Within 72 h, hyphal bodies and hyphae could be found throughout the infected organism including in the midgut, Malphigian tubules, alimentary canal, ovarioles (in females), and an extended hyphal network could be seen on insect cadavers (>72 h post-infection). Real-time RT-PCR analyses of the expression of select genes implicated in virulence including the Pr1 protease, beauvericin synthase, involved in the production of the secondary metabolite beauvericin, two cytochrome P450 monooxygenases implicated in cuticular hydrocarbon degradation, two multidrug efflux proteins, a perilipin involved in lipid storage, and the Hog1 MAP kinase and protein kinase A signaling factors revealed discrete patterns of infection-time dependent expression. These data provide basic insights into the process of B. bassiana infection of F. occidentalis.


HortScience ◽  
2020 ◽  
Vol 55 (8) ◽  
pp. 1323-1326
Author(s):  
Nathan J. Herrick ◽  
Raymond A. Cloyd

Western flower thrips, Frankliniella occidentalis, and fungus gnats (Bradysia spp.) are major insect pests of greenhouse production systems. Both insect pests have life stages that reside in the soil or plant-growing medium: prepupae and pupae of western flower thrips and fungus gnat larvae. There are unsubstantiated allegations made by a manufacturer that certain plant-growing media that contain a bacterium, Bacillus pumilus, and arbuscular mycorrhizal fungus, Glomus intraradices, negatively affect the survival of western flower thrips pupae and fungus gnat larvae. Therefore, we conducted a study involving laboratory experiments replicated over time (2019 and 2020) to investigate the influence of the plant-growing media Pro-Mix BX + Mycorrhizae and Pro-Mix BX + Biofungicide + Mycorrhizae on western flower thrips pupae and fungus gnat larvae. All experiments involved placing western flower thrips pupae or fungus gnat larvae (second and third instar) into 473-mL deli containers with the different treatments (plant-growing media). A 5 × 4-cm section of a yellow sticky card was affixed to the lid of each deli container. After 21 days, the number of western flower thrips or fungus gnat adults that emerged from the growing media and were captured on the yellow sticky cards was recorded. The use of the yellow sticky card was an indirect assessment of western flower thrips pupal or fungus gnat larval mortality. We found none of the plant-growing media tested that contained a bacterium and/or arbuscular mycorrhizal fungus affected the survival of western flower thrips pupae or fungus gnat larvae. Therefore, greenhouse producers should be leery of information provided by manufacturers that does not contain valid, scientifically based data.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0239958
Author(s):  
Mika Murata ◽  
Kotaro Konno ◽  
Naoya Wasano ◽  
Atsushi Mochizuki ◽  
Ichiro Mitsuhara

Insect pests cause serious damage in crop production, and various attempts have been made to produce insect-resistant crops, including the expression of genes for proteins with anti-herbivory activity, such as Bt (Bacillus thuringiensis) toxins. However, the number of available genes with sufficient anti-herbivory activity is limited. MLX56 is an anti-herbivory protein isolated from the latex of mulberry plants, and has been shown to have strong growth-suppressing activity against the larvae of a variety of lepidopteran species. As a model of herbivore-resistant plants, we produced transgenic tomato lines expressing the gene for MLX56. The transgenic tomato lines showed strong anti-herbivory activities against the larvae of the common cutworm, Spodoptera litura. Surprisingly, the transgenic tomato lines also exhibited strong activity against the attack of western flower thrips, Frankliniera occidentalis. Further, growth of the hadda beetle, Henosepilachna vigintioctopunctata, fed on leaves of transgenic tomato was significantly retarded. The levels of damage caused by both western flower thrips and hadda beetles were negligible in the high-MLX56-expressing tomato line. These results indicate that introduction of the gene for MLX56 into crops can enhance crop resistance against a wide range of pest insects, and that MLX56 can be utilized in developing genetically modified (GM) pest-resistant crops.


2006 ◽  
Vol 16 (4) ◽  
pp. 633-636 ◽  
Author(s):  
Brian K. Hogendorp ◽  
Raymond A. Cloyd

Sanitation, which includes removing plant and growing medium debris, is an important component of any greenhouse or nursery pest management program. However, there is minimal quantitative information on how sanitation practices can reduce pest problems. In this study, conducted from May through Nov. 2005, we evaluated plant and growing medium debris as a source of insect pests from four greenhouses located in central Illinois. Two 32-gal refuse containers were placed in each greenhouse with a 3 × 5-inch yellow sticky card attached to the underside of each refuse container lid. Each week, yellow sticky cards and plastic refuse bags were collected from the containers and insects captured on the yellow sticky cards were identified. Insects captured on the yellow sticky cards were consistent across the four greenhouses with western flower thrips (Frankliniella occidentalis), fungus gnats (Bradysia spp.), and whiteflies (Bemisia spp.) the primary insects present each week. Insect numbers, in order of prevalence on the yellow sticky cards, varied across the four locations, which may be related to the type of plant debris discarded. For example, extremely high numbers of adult whiteflies (range = 702 to 1930) were captured on yellow sticky cards in one greenhouse each month from August through November. This was due to the presence of yellow sage (Lantana camera), bee balm (Monarda didyma), garden verbena (Verbena × hybrida), common zinnia (Zinnia elegans), sage (Salvia spp.) and fuchsia (Fuschia spp.) debris that was heavily-infested with the egg, nymph, pupa, and adult stages of whiteflies. High western flower thrips adult numbers in the greenhouses were generally associated with plant types such as marguerite daisy (Dendranthema frutescens) and pot marigold (Calendula officinalis) disposed while in bloom with opened yellow flowers, which contained adult western flower thrips. Based on the results of this study, it is important that greenhouse producers timely remove plant and growing medium debris from greenhouses or place debris into refuse containers with tight-sealing lids to prevent insect pests from escaping.


2005 ◽  
Vol 40 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Daniel F. Warnock ◽  
Raymond A. Cloyd

Greenhouse managers mix together pesticides to broaden the spectrum of pest control and to reduce pesticide and labor costs. However, the efficacy of pesticide mixtures has not been well-documented. This study assesses how mixtures of commercially available insecticides and miticides in two, three, and four-way combinations affected the control of western flower thrips, Frankliniella occidentalis Pergande, in greenhouse experiments and in a laboratory bioassay. The pesticides screened in the greenhouse experiments and laboratory bioassay were spinosad, abamectin, bifenazate, azadirachtin and imidacloprid. Each pesticide was applied at the maximum label-recommended rate. In the greenhouse experiments, transvaal daisy (Gerbera jamesonii H. Bolus ex Hook. f) and lisianthus (Eustoma grandiflorum G. Don ex Sweet) flowers were infested with 25 adult western flower thrips (mixture of females and males). Flowers were then sprayed with the designated treatments. After 72 h, flowers were dissected to assess the numbers of live and dead western flower thrips. In the laboratory bioassay, chrysanthemum (Dendranthema grandiflora Tzvelev) leaf sections, treated with solutions of each pesticide and all possible combinations, were exposed to 15 adult western flower thrips. The numbers of live and dead western flower thrips were assessed after 48 h. For all three experiments, we were not able to identify any antagonistic pesticide combinations. All treatments with spinosad, including the individual application and pesticide mixtures, resulted in high mortality of western flower thrips. Our data suggest that combinations of spinosad with the other pesticides tested do not affect the efficacy of spinosad in controlling western flower thrips. This information is important to greenhouse managers who wish to mix pesticides and still control western flower thrips in addition to the other plant-feeding arthropods found in greenhouses.


2007 ◽  
Vol 42 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Heather E. Lash ◽  
Daniel F. Warnock ◽  
Raymond A. Cloyd

This study was conducted to determine the effect of 2 insecticides/miticides, spinosad and abamectin, and 2 fungicides, thiophanate-methyl and fenhexamid, when applied alone or mixed in all combinations, on the survival of Neoseiulus cucumeris (Oudemans). Neoseiulus cucumeris is a predatory mite utilized in greenhouses for managing western flower thrips, Frankliniella occidentalis Pergande. The deutonymph and adult stages of N. cucumeris were directly exposed to the pesticide treatments or a water control. Overall, the deutonymphs were more susceptible to the pesticide treatments, based on percent survival 24 h after treatment, than the adults. Five of the 7 pesticide mixtures containing spinosad and 4 of the 7 mixtures containing abamectin resulted in deutonymph mortality values between 50 and 69%. Thiophanate-methyl alone and in combination with either spinosad or abamectin resulted in >35% mortality of the deutonymphs. Based on the results of this study, spinosad and abamectin, when used alone or in mixture with thiophanate-methyl will reduce N. cucumeris populations by killing the deutonymphs. This information is important to greenhouse managers who want to use pesticide mixtures to manage arthropod pests and fungal pathogens without disrupting biological control programs for western flower thrips.


HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 890-895 ◽  
Author(s):  
Yinping Li ◽  
Raymond A. Cloyd ◽  
Nora M. Bello

Western flower thrips, Frankliniella occidentalis, is one of the most destructive insect pests of greenhouse-grown horticultural crops. The primary method of managing western flower thrips populations involves applications of insecticides; however, there is no information associated with the effect of the insect growth regulator, pyriproxyfen, or the entomopathogenic fungus, Isaria fumosorosea, on western flower thrips pupae in growing media. Therefore, four laboratory experiments were conducted to determine the effect of pyriproxyfen and I. fumosorosea applied as a drench to growing media on western flower thrips pupae. Expt. 1 evaluated the efficacy of pyriproxyfen and I. fumosorosea on western flower thrips pupae. Based on the results from Expt. 1, Expt. 2 assessed the effect of pyriproxyfen in two growing media (LC1 and BM1) on western flower thrips pupae. Expts. 3 and 4 determined the residual activity of pyriproxyfen in growing media on western flower thrips pupae 3, 5, 7, and 14 days after treatments were applied. The pyriproxyfen treatment resulted in a significantly lower estimated mean probability of western flower thrips adults captured on yellow sticky cards (17%) compared with the water control (59%), untreated check (88%), and two I. fumosorosea treatments (46% for 1.0 g and 41% for 2.0 g of Ancora) in Expt. 1. However, for the two growing media in Expt. 2, the estimated mean probability of western flower thrips adults captured on yellow sticky cards was not significantly different between the pyriproxyfen treatment (LC1 = 15%; BM1 = 12%) and the water control (LC1 = 41%; BM1 = 24%). For either the pyriproxyfen treatment or the untreated check, there was no evidence of a significant difference between the two growing media on the estimated mean probability of western flower thrips adults captured on yellow sticky cards. Furthermore, there was no evidence of any residual activity 3 days after drench applications of pyriproxyfen. The results of the study have demonstrated that drench applications of pyriproxyfen are not affecting survival of western flower thrips pupae.


1990 ◽  
Vol 122 (6) ◽  
pp. 1111-1117 ◽  
Author(s):  
A.B. Broadbent ◽  
J.A. Matteoni ◽  
W.R. Allen

AbstractA wide range in feeding damage as defined by leaf scars among 27 cultivars of florist’s chrysanthemum was apparent for the western flower thrips, Frankliniella occidentalis (Pergande). Assessments based on numbers of feeding scars or ranking of cultivars on the basis of the leaf area damaged by feeding were in close agreement. Cultivars with the most feeding damage under growth room conditions, such as cvs. White Marble and Polaris, were the same as those in plots within a naturally infested commercial greenhouse. Under growth room conditions, a 2- to 4-week exposure of plants to a population of thrips was sufficient to evaluate feeding damage. Closely related cultivars had similar levels of feeding damage, and foliage of yellow-flowered cultivars was significantly more attractive to thrips for feeding than foliage of white-flowered sister cultivars during the pre-bloom period. There was a low correlation between feeding damage and incidence of the tomato spotted wilt virus among cultivars in both growth room and greenhouse tests, indicating that virus susceptibility of cultivars was epidemiologically more significant than the feeding activity of western flower thrips.


2020 ◽  
Author(s):  
Mika Murata ◽  
Kotaro Konno ◽  
Naoya Wasano ◽  
Atsushi Mochizuki ◽  
Ichiro Mitsuhara

AbstractInsect pests cause serious damage in crop production, and various attempts have been made to produce insect-resistance crops, including the expression of genes for proteins with anti-herbivory activity, such as BT toxins. However, the number of available genes with sufficient anti-herbivory activity is limited. MLX56 is an anti-herbivory protein isolated from the latex of mulberry plants, and has been shown to have a strong growth-suppressing activity against the larvae of a variety of lepidopteran species. As a model of herbivore-resistant plants, we produced transgenic tomato lines expressing the gene for MLX56. The transgenic tomato lines showed strong anti-herbivory activities against the larvae of the common cutworm, Spodoptera litura. Surprisingly, the transgenic tomato lines also exhibited strong activity against the attack of the western flower thrips, Frankliniera occidentalis. Further, growth of the hadda beetle, Henosepilachna vigintioctopunctata fed on leaves of transgenic tomato was significantly retarded. The levels of damage caused by both western flower thrips and hadda beetles were negligible in the high-MLX56-expressing tomato line. These results indicate that introduction of the gene for MLX56 into crops can enhance crop resistance against a wide range of pest insects, and that MLX56 can be utilized in developing pest-resistance GM crops.


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