scholarly journals Comparative Efficacy Trials with Two Different Bacillus thuringiensis Serovar kurstaki Strains against Gypsy Moth in Mediterranean Cork Oak Forests

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 602
Author(s):  
Maurizio Olivieri ◽  
Roberto Mannu ◽  
Luca Ruiu ◽  
Pino A. Ruiu ◽  
Andrea Lentini
Keyword(s):  
Bacillus Thuringiensis ◽  
Gypsy Moth ◽  
Untreated Control ◽  
Larval Density ◽  
Resistance Management ◽  
Cost Savings ◽  
Cork Oak ◽  
Oak Forests ◽  
Density Reduction ◽  
Untreated Check

The efficacy of two formulations (Foray® 76B AVIO and Rapax® AS AIR) containing different Bacillus thuringiensis kurstaki (Btk) strains (ABTS-351 and EG-2348, respectively) was evaluated against Lymantria dispar larval populations in cork oak forests in Sardinia (Italy), in 2018 and 2019. The experimental design involved the following treatments: (I) untreated control; (II) Foray® 76B at the dose of 2.0 L/ha; (III) Foray® 76B at the dose of 2.5 L/ha; (IV) Rapax® AS AIR at the dose of 2.0 L/ha. Aerial applications were carried out using a helicopter equipped with four electronic rotary atomizers adjusted to sprinkle 160 micron-sized drops. Btk efficacy was evaluated by assessing the larval density reduction 7, 14, and 21 days after the application in each experimental plot in comparison with an untreated check. In addition to field surveys, the mortality of second and third instar larval samples, randomly collected from each plot after treatment and fed with foliage from the same plot, was determined in the laboratory. All Btk treatments were similarly effective, and no differences in larval density reduction among Btk strains and doses were found in either year. Twenty-one days after application, the average larval density reduction in the field was approximately 70% in all treated plots in 2018, whereas in 2019 it reached 80% only in areas treated with Foray 76B at 2.5 L/ha. Laboratory observations showed that all Btk-based products were effective against gypsy moth larvae, with significant differences in mortality between untreated control and the different Btk treatments. Our results shed light on the possibility of alternating different Btk strains for resistance management purposes and of applying lower doses than labeled, in order to achieve cost savings for product shipment and distribution and to reduce the environmental impact.

Influence of Bacillus thuringiensis application timing on population dynamics of gypsy moth in Mediterranean cork oak forests

2019 ◽  
Vol 76 (3) ◽  
pp. 1103-1111
Author(s):  
Roberto Mannu ◽  
Arturo Cocco ◽  
Pietro Luciano ◽  
Andrea Lentini
Keyword(s):  
Population Dynamics ◽  
Bacillus Thuringiensis ◽  
Gypsy Moth ◽  
Cork Oak ◽  
Oak Forests ◽  
Application Timing

scholarly journals Effectiveness of Diflubenzuron and Bacillus thuringiensis Against Gypsy Moth Populations

1997 ◽  
Vol 14 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Kevin W. Thorpe ◽  
Richard L. Ridgway ◽  
Ralph E. Webb
Keyword(s):  
Bacillus Thuringiensis ◽  
Population Density ◽  
Gypsy Moth ◽  
Mass Density ◽  
Larval Mortality ◽  
Larval Density ◽  
Egg Mass ◽  
Percent Reduction ◽  
Moth Population ◽  
Oak Trees

Abstract Aerial applications of Bacillus thuringiensis Berliner subsp. kurstaki (74.1 billion international units/ha per application; single and double applications), diflubenzuron [69 g (ai)/ha], and no treatment were evaluated. Treatment effects were estimated from frass collections, defoliation, counts of pupae under burlap, and egg-mass counts. Estimates of larval density in the canopy 20 days after treatment ranged from 318.3 to 55.5 larvae per m² in the control- and diflubenzuron-treated plots, respectively. Larval density was reduced in all treatments, and was lowest in the plots treated with diflubenzuron and two applications of B. thuringiensis. Population density rapidly declined in the control plots, and by June 20, when larvae were predominantly in the fifth and sixth instars, no significant differences in larval density were detected among the treatments. Significantly less defoliation occurred to oak trees in the treated plots, but no differences were detected among the spray treatments. Counts of pupae under burlap, postseason egg-mass counts, and percent reduction in egg-mass density did not differ significantly among treatments or versus controls. These results suggest that diflubenzuron and double B. thuringiensis treatments caused higher levels of larval mortality than occurred with a single B. thuringiensis application, but that with a naturally declining gypsy moth population the final levels of damage were the same under all treatments. North. J. Appl. 14(3):135-140.

scholarly journals Gypsy Moth Management with LdMNPV Baculovirus in Cork Oak Forest

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 495
Author(s):  
Luca Ruiu ◽  
Roberto Mannu ◽  
Maurizio Olivieri ◽  
Andrea Lentini
Keyword(s):  
Population Dynamics ◽  
Gypsy Moth ◽  
Block Design ◽  
Larval Mortality ◽  
Larval Density ◽  
Management Program ◽  
Cork Oak ◽  
Forest Protection ◽  
Randomized Block Design ◽  
Species Specific

(1) Research Highlights: Applications of a species-specific baculovirus is a promising method to control the gypsy moth and regulate its population dynamics in forest ecosystems. (2) Background and Objectives: Cork oak protection against the Lepidopteran defoliator Lymantria dispar requires an appropriate forest ecosystem management program, involving the application of eco-sustainable microbial products during population outbreaks. The species-specific multicapsid nucleopolyhedrovirus (LdMNPV), agent of natural epizootics in gypsy moth populations, represents an option that was investigated in a multi-year field study, involving viral applications either from the ground or by aerial treatment. (3) Materials and Methods: Efficacy trials against L. dispar populations were conducted in 2018 and 2019 in Sardinia, according to a randomized block design. Each year, two trials were conducted, applying a baculovirus commercial formulation with an atomizer from the ground and assessing the effects of different doses and application timing, respectively. An aerial application trial distributing LdMNPV at ultra-low volumes (2 L/ha) was also conducted in 2019 to assess the virus efficacy at a larger field scale. (4) Results: In both years, a significant increase in larval mortality was detected in plots treated with higher viral occlusion body (OB) doses and with an earlier application targeting younger larvae, in comparison with untreated controls. Due to an observed retrogradation phase of the target pest in 2019, no significant differences in larval density between areas treated from a helicopter and control were detected, but in the few weeks following application, a meaningful vitality decrease in larval samples from treated plots was observed. (5) Conclusions: Based on the results of this study, the use of LdMNPV in forest protection programs against gypsy moth can be worth consideration in multi-year integrated program strategies to modulate population dynamics.

Detection of oomycide-insensitive Phytophthora isolates in Maryland ornamental nurseries and Mid-Atlantic landscapes provide data for reconsidering management strategies

2021 ◽  
Author(s):  
Justine Beaulieu ◽  
Johanna Del Castillo Munera ◽  
Yilmaz Balci
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Resistance Management ◽  
Phytophthora Species ◽  
Oak Forests ◽  
Relative Growth ◽  
Off Label ◽  
Potting Media ◽  
Almost All

Five Phytophthora species comprising a total of 243 isolates (77 P. cinnamomi, 23 P. citrophthora, 18 P. multivora, 18 P. pini, and 107 P. plurivora) were screened for sensitivity to mefenoxam, fosetyl-Al, dimethomorph, dimethomorph + ametoctradin and fluoxastrobin using amended agar assays. Mefenoxam-insensitive isolates were detected within P. cinnamomi (4%), P. multivora (11%), and P. plurivora (12%) even at approximately 2.5x the recommended label rate. These isolates were also insensitive to higher (off-label) concentrations of fluoxastrobin. Concentrations of dimethomorph (400 g/mL) and dimethomorph + ametoctradin (100 g/mL) were mostly effective in mycelial growth inhibition, but two P. plurivora isolates were insensitive, suggesting that resistance management is required. All mefenoxam-insensitive isolates were sensitive to fosetyl-Al at the label rate. Surprisingly, the populations of P. cinnamomi from mid-Atlantic oak forests included insensitive isolates. With almost all species, isolates recovered from asymptomatic hosts (e.g., soil/potting media collected of randomly selected asymptomatic hosts) had a significantly greater relative growth rate when compared to isolates recovered from symptomatic hosts (e.g., isolates recovered from lesions or wilted plants). These findings suggest that mefenoxam should no longer be used to manage oomycetes in Maryland ornamental nurseries and that the use of fluoxastrobin should be limited.

Forecasting infestation byCoraebus undatus(Coleoptera, Buprestidae) in cork oak forests

2012 ◽  
Vol 58 (3) ◽  
pp. 275-280 ◽  
Author(s):  
A. Gallardo ◽  
A. Jiménez ◽  
C.A. Antonietty ◽  
M. Villagrán ◽  
M.E. Ocete ◽  
...  
Keyword(s):  
Cork Oak ◽  
Oak Forests

scholarly journals Efficacy of newer insecticides against sucking pests of rice fallow blackgram (Vigna mungo L.)

2018 ◽  
Author(s):  
K. Swathi ◽  
P. Seetharamu ◽  
S. Dhurua ◽  
M. Suresh
Keyword(s):  
Field Experiment ◽  
Bemisia Tabaci ◽  
Untreated Control ◽  
Disease Incidence ◽  
Vigna Mungo ◽  
Experimental Results ◽  
Agricultural College ◽  
Untreated Check ◽  
Cent Disease ◽  
Thrips Population

A field experiment was conducted to determine the efficacy of different insecticides against sucking pests viz., thrips, Caliothrips indicus Bangall and whitefly Bemisia tabaci Gennadius, infesting blackgram in North coastal Andhrapradesh at Agricultural College, Naira during rabi 2017-2018.The experimental results revealed that all the treatments showed significant differences in reducing the population of sucking pests over untreated check. Among the tested insecticides, thiacloprid 21.7 SC @ 0.0325% was found to be highly effective against thrips by reducing74.80 per cent thrips population followed by acetamiprid 4 % + fipronil 4% @ 2ml l-1 with 70.81 per cent over untreated control, whereas flonicamid 50 WG @ 0.0325% was very effective against the population of whitefly byreducing 72.19 per cent and lowest per cent disease incidence (17.66%) followed by acetamiprid 4% + fipronil 4% @ 2ml l-1 (64.94%) and thiamethoxam 25 WG @ 0.005% (62.21%) which were on par with each other over control.

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