Impact of Vineyard Pesticides on a Beneficial Arthropod, Typhlodromus pyri (Acari: Phytoseiidae), in Laboratory Bioassays

2011 ◽  
Vol 104 (3) ◽  
pp. 970-977 ◽  
Author(s):  
Angela N. Gadino ◽  
Vaughn M. Walton ◽  
Amy J. Dreves
Keyword(s):  
Typhlodromus Pyri ◽  
Laboratory Bioassays ◽  
Beneficial Arthropod

Mancozeb resistance patterns among Kampimodromus aberrans and Typhlodromus pyri (Acari: Phytoseiidae) strains from French vineyards

2004 ◽  
Vol 136 (5) ◽  
pp. 663-673 ◽  
Author(s):  
Philippe Auger ◽  
Romain Bonafos ◽  
Serge Kreiter
Keyword(s):  
Application Rate ◽  
Field Application ◽  
Typhlodromus Pyri ◽  
Phytoseiid Mites ◽  
Kampimodromus Aberrans ◽  
Resistance Factors ◽  
Resistance Patterns ◽  
Resistant Strains ◽  
Maximum Field ◽  
Laboratory Bioassays

AbstractLaboratory bioassays were carried out on two species of phytoseiid mites to investigate their resistance to the fungicide mancozeb. Susceptible and suspected resistant strains of Kampimodromus aberrans (Oudemans) and Typhlodromus pyri Scheuten were tested. Mancozeb resistance factors were low to moderate: they reached 6.3 and 11.7 for K. aberrans and T. pyri, respectively. Intrinsic toxicity of mancozeb was approximately 5–10-fold more pronounced in females of K. aberrans than in females of T. pyri. The female susceptibility pattern of the most resistant strain of K. aberrans was quite close to that of the most susceptible strain of T. pyri. The LC50 values for the most resistant strains of K. aberrans and T. pyri were 4.6 and 43 times higher, respectively, than the maximum field application rate of mancozeb recommended for control of downy mildew in vineyards. Using a diagnostic concentration, a limited survey in vine plots indicated that most of the K. aberrans strains we tested were susceptible to mancozeb, but a few consisted of both resistant and susceptible individuals. All strains of T. pyri collected in Burgundy were susceptible. Half of the T. pyri strains from Bordeaux were susceptible and the other half were mixed populations of resistant and susceptible individuals.

Effects of encapsulation on the toxicity of insecticides to the Oriental fruit moth (Lepidoptera: Tortricidae) and the predator Typhlodromus pyri (Acari: Phytoseiidae)

2001 ◽  
Vol 133 (6) ◽  
pp. 819-826 ◽  
Author(s):  
M.K. Pogoda ◽  
D.J. Pree ◽  
D.B. Marshall
Keyword(s):  
First Generation ◽  
Typhlodromus Pyri ◽  
Oriental Fruit Moth ◽  
Susceptible Population ◽  
Emulsifiable Concentrate ◽  
Lambda Cyhalothrin ◽  
Predaceous Mite ◽  
Neonate Larvae ◽  
Two Populations ◽  
Laboratory Bioassays

AbstractWe assessed the effects of microencapsulation on the toxicity of chlorpyrifos, cypermethrin, and lambda-cyhalothrin to larvae of the Oriental fruit moth, Grapholita molesta (Busck), in the laboratory and the field. We also compared the toxicity of microencapsulated and traditional formulations to pyrethroid-susceptible and pyrethroid-resistant populations of the predaceous mite Typhlodromus pyri Scheuten in the laboratory. In laboratory bioassays with neonate larvae of G. molesta, the microencapsulated formulations of chlorpyrifos and cypermethrin were less toxic than the wettable-powder and emulsifiable-concentrate formulations. The emulsifiable-concentrate and microencapsulated formulations of lambda-cyhalothrin were equally toxic. In the field, all trees in insecticide-treated plots contained less damage by first generation G. molesta larvae than unsprayed controls. In the second generation, the microencapsulated formulations of cypermethrin and chlorpyrifos were generally less effective than the emulsifiable-concentrate formulation of cypermethrin. The microencapsulated formulation of lambda-cyhalothrin was as effective as the emulsifiable-concentrate formulation. The microencapsulated formulation of cypermethrin was less toxic than the emulsifiable-concentrate formulation to both pyrethroid-susceptible and pyrethroid-resistant populations of T. pyri. Both populations were highly resistant to chlorpyrifos and unaffected by either formulation. The microencapsulated formulation of lambda-cyhalothrin affected the two populations of T. pyri differently; the microencapsulated formulation was approximately fivefold more toxic than the emulsifiable-concentrate formulation to the pyrethroid-susceptible population, but sixfold less toxic than the emulsifiable-concentrate formulation to the pyrethroid-resistant population. Much of the selectivity reported for the microencapsulated formulations of cypermethrin and chlorpyrifos appeared related to a general reduction in toxicity to both target insects and beneficial mites. The microencapsulated lambda-cyhalothrin was as toxic as the emulsifiable-concentrate formulation to the target insect but was less toxic than the emulsifiable concentrate to pyrethroid-resistant predator mites. This limited increased selectivity may be useful where resistant populations of predators occur.

In Vitro Screening of Azalea for Resistance to Azalea Lace Bug

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 506b-506
Author(s):  
Carol D. Robacker ◽  
S.K. Braman
Keyword(s):  
Leaf Damage ◽  
In Vitro Screening ◽  
Screening Assay ◽  
Delaware Valley ◽  
In Vitro Techniques ◽  
Culture Tube ◽  
Lace Bug ◽  
Lace Bugs ◽  
Laboratory Bioassays

Azalea lace bug (Stephanitis pyrioides) is the most serious pest on azalea. Results of laboratory bioassays and field evaluations of 17 deciduous azalea taxa have identified three resistant taxa: R. canescens, R. periclymenoides, and R. prunifolium. Highly susceptible taxa are `Buttercup', `My Mary', R. oblongifolium, and the evergreen cultivar `Delaware Valley White'. To determine whether in vitro techniques would have potential value in screening or selecting for resistance, or for the identification of morphological or chemical factors related to resistance, an in-vitro screening assay was developed. In-vitro shoot proliferation was obtained using the medium and procedures of Economou and Read (1984). Shoots used in the bioassays were grown in culture tubes. Two assays were developed: one for nymphs and one for adult lace bugs. To assay for resistance to nymphs, `Delaware Valley White' leaves containing lace bug eggs were disinfested with 70% alcohol and 20% commercial bleach, and incubated in sterile petri plates with moistened filter paper until the nymphs hatched. Five nymphs were placed in each culture tube, and cultures were incubated for about 2 weeks, or until adults were observed. To assay for resistance to adults, five female lace bugs were placed in each culture tube and allowed to feed for 5 days. Data collected on survival and leaf damage was generally supportive of laboratory bioassays and field results. Adult lace bugs had a low rate of survival on resistant taxa. Survival of nymphs was somewhat reduced on resistant taxa.

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