scholarly journals Efficacy of Horticultural Oil and Insecticidal Soap against Selected Armored and Soft Scales

2017 ◽  
Vol 27 (5) ◽  
pp. 618-624 ◽  
Author(s):  
Carlos R. Quesada ◽  
Clifford S. Sadof
Keyword(s):  
Insect Pests ◽  
Chemical Properties ◽  
Scale Insects ◽  
Effective Management ◽  
Pine Needle ◽  
Soft Scale ◽  
Armored Scale ◽  
Aspidiotus Nerii ◽  
High Control ◽  
Calico Scale

Insecticidal soap and horticultural oil have the potential to kill individuals within populations of soft-bodied insect pests by suffocation. However, scientific literature is inconsistent about the efficacy of insecticidal soaps and petroleum-based oils against armored scale (Hemiptera: Diaspidae) and soft scale (Hemiptera: Coccidae). We examined the efficacy of horticultural oil and insecticidal soap against armored and soft scales at different developmental life stages. Studies were conducted in the laboratory and field with two species of armored scale [pine needle scale (Chionaspis pinifoliae) and oleander scale (Aspidiotus nerii)] and two species of soft scale [calico scale (Eulecanium cerasorium) and striped pine scale (Toumeylla pini)]. All insecticide applications were made at a rate of 2 gal per 100 gal water. Our laboratory results suggested that horticultural oil and insecticidal soap killed both calico scale (73% and 93%, respectively) and oleander scale (67% and 78%, respectively) when insecticides targeted 1-day-old scales. Scale insects built up tolerance to both materials over time after they settled. However, our field data indicated that horticultural oil had high control of settled armored scale [oleander scale (90%) and pine needle scale (83%)], but failed to control settled soft scale [stripe pine scale (5%)]. Insecticidal soap reduced armored scale [oleander scale (54%)]. Neither horticultural oil nor insecticidal soap significantly reduced populations of adult armored or soft scales compared with a control. Overall, horticultural oil killed a greater percentage of armored scales than soft scales, whereas insecticidal soap gave greater control against soft scales. We suggest that differences were driven by chemical properties of both insect integuments and insecticides. The waxy cover of an armored scale might reduce penetration of polar insecticidal soap whereas polar integument of a soft scale might impede infiltration of the lipophilic horticultural oil. Consequently, timing application to crawler stage is important for effective management of armored or soft scale with horticultural oils and insecticidal soaps.

scholarly journals Factors Influencing Insecticide Efficacy against Armored and Soft Scales

2018 ◽  
Vol 28 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Carlos R. Quesada ◽  
Adam Witte ◽  
Clifford S. Sadof
Keyword(s):  
Ornamental Plants ◽  
Scale Insects ◽  
Pine Needle ◽  
Pesticide Application ◽  
Juvenile Period ◽  
First Instar ◽  
Insecticide Efficacy ◽  
Aspidiotus Nerii ◽  
Calico Scale ◽  
Phloem Feeding

Scale insects (Hemiptera: Coccoidea) are among the most economically important pests of ornamental plants. Soft scales (Coccidae) are phloem-feeding insects that produce large amounts of honeydew. By contrast, armored scales (Diaspididae) feed on the contents of plant cells and produce a waxy test that covers their bodies. We studied two species of armored scales [pine needle scale (Chionaspis pinifoliae) and oleander scale (Aspidiotus nerii)] and two species of soft scales [calico scale (Eulecanium cerasorum) and striped pine scale (Toumeyella pini)] to compare efficacy of selected insecticides. In addition, we assessed how the duration of first instar emergence might influence insecticide efficacy. Several reduced-risk insecticides (chlorantraniliprole, pyriproxyfen, spiromesifen, and spirotetramat), horticulture oil, and two broad-spectrum insecticide standards (bifenthrin and dinotefuran) were evaluated. Efficacy of insecticides was consistent within each scale family. Bifenthrin and pyriproxyfen were the only insecticides that killed soft scale insects. By contrast, all insecticides killed armored scales when the crawler stage was the target of application. Armored and soft scales may differ in susceptibility to pesticides because of likely differences in the chemical composition of their integuments and covers. Finally, we found that the effectiveness of a single application of insecticide declined by >15% when the duration of the crawling juvenile period was increased from 1 to 4 weeks. Increases in duration of a scale crawling period decreased the efficacy of a pesticide application.

scholarly journals Suitability of Five Horticulturally Important Armored Scale Insects as Hosts for an Exotic Predaceous Lady Beetle1

1993 ◽  
Vol 11 (1) ◽  
pp. 28-30 ◽  
Author(s):  
Brenda C. Bull ◽  
Michael J. Raupp ◽  
Mark R. Hardin ◽  
Clifford S. Sadof
Keyword(s):  
Pupal Stage ◽  
The United States ◽  
Scale Insects ◽  
Armored Scale ◽  
Aspidiotus Nerii ◽  
Pseudaulacaspis Pentagona ◽  
Chilocorus Kuwanae ◽  
San Jose Scale ◽  
White Peach Scale ◽  
Euonymus Scale

Abstract Chilocorus kuwanae (Sylvestri) was imported from Korea to the United States for release against the euonymus scale (Unaspis euonymi (Comstock)). Field observations suggest that C. kuwanae feeds on a number of other armored scale insects, including white peach scale (Pseudaulacaspis pentagona (Targionni-Tozzeti)) and obscure scale (Melanaspis obscura (Comstock)). However, such observations have not been rigorously examined under controlled conditions. Our laboratory investigations indicate that C. kuwanae survives and reproduces well on San Jose scale (Quadraspidiotus perniciosus (Comstock)), in addition to euonymus scale. Fecundity was reduced in adults fed white peach scale. Few larvae survived to adulthood when fed oleander scale (Aspidiotus nerii (Bouche)). Adults failed to reproduce on obscure scale; none of the larvae fed this host survived to the pupal stage.

scholarly journals Abundance, seasonality and parasitism of Diaspididae (Hemiptera) on olive trees

2019 ◽  
Vol 25 (1/2) ◽  
pp. 85-93
Author(s):  
Gabriela Chesim De Souza ◽  
Luiza Rodrigues Redaelli ◽  
Vera Regina dos Santos Wolff
Keyword(s):  
Outer Part ◽  
Scale Insects ◽  
Rio Grande Do Sul ◽  
Parasitism Rate ◽  
Temperature Variations ◽  
Armored Scale ◽  
Aspidiotus Nerii ◽  
Recent Activity ◽  
Olive Trees ◽  
Total Parasitism

Olive culture is a recent activity in Rio Grande do Sul, Brazil with little information on its scale insects. Abundance and seasonality of armored scale insects (Hemiptera, Diaspididae) and their parasitism was evaluated in olive orchard, Olea europaea L., cultivar Arbequina, in Caçapava do Sul (30°30′43″ S, 53°29′27″ W), RS, Brazil. Samples were monthly collected from April 2012 to March 2013. At each occasion 20 trees were drawn and, from each quadrant of their canopies (northern, southern, eastern and western) two branches (20 - 30 cm - length and contained at least 20 leaves) were randomly removed, respectively from the inner part and the outer part of the canopy. We found five species of Diaspididae, Aonidiella aurantii (Maskell), Hemiberlesia cyanophylli (Signoret), Acutaspis paulista (Hempel), Aspidiotus nerii Bouché and Melanaspis obscura (Comstock). It was not found an unique pattern of abundance, indicating that these species respond differently to temperature variations between seasons. The armored scale insects were evenly distributed among quadrants. Only H. cyanophylli showed differences in abundance between the inner and outer branches. We registered parasitism in all Diaspididae species; the total parasitism rate was 9.78%.

scholarly journals Biological Control of Armored Scale Insects in Mexico

1968 ◽  
Vol 61 (4) ◽  
pp. 1086-1088 ◽  
Author(s):  
H. L. Maltby ◽  
Eteazar Jimenez-Jimenez ◽  
Paul DeBach
Keyword(s):  
Biological Control ◽  
Scale Insects ◽  
Armored Scale

Bionomics of the pine needle scale (Hemiptera: Diaspididae), an emerging pest in Christmas tree (Pinaceae) plantations in southern Québec, Canada

2018 ◽  
Vol 150 (5) ◽  
pp. 632-636 ◽  
Author(s):  
Jean-Frdéric Guay ◽  
Amy Bernier-Desmarais ◽  
Jean-François Doherty ◽  
Conrad Cloutier
Keyword(s):  
Life Cycle ◽  
Scale Insects ◽  
Tree Plantations ◽  
Christmas Tree ◽  
Pine Needle ◽  
Abies Fraseri ◽  
Fraser Fir ◽  
Christmas Trees ◽  
Significant Damage ◽  
The Status

AbstractThe pine needle scale, Chionaspis pinifoliae (Fitch) (Hemiptera: Diaspididae), has the status of an emerging pest in Christmas tree (Pinaceae) plantations in Québec, Canada. The scale is not known to cause any significant damage yet and is not generally monitored by growers. However, it can be an obstacle for exportation to Christmas tree markets where scale insects are strictly regulated. In this study, we describe its life cycle in Christmas tree plantations in southern Québec. We confirm the presence of both parthenogenetic and sexual forms of the scale on Fraser fir Abies fraseri (Pursh) Poiret (Pinaceae) grown as Christmas trees, and of parasitoid and Coccinellidae (Coleoptera) specialists that could contribute to its control.

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