Additive and synergistic interactions of entomopathogenic fungi with Bacillus thuringiensis for the control of the European grapevine moth Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae)

Abstract Background The European grapevine moth, Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) is currently the most damaging pest in many viticultural regions across the Mediterranean basin and elsewhere. Its feeding activity also enhances the development of secondary infections by Botrytis cinerea - and other fungi - to wine grapes. The gram-positive bacterium Bacillus thuringiensis (Bt) has been reported to partially control larval populations of L. botrana, while it requires to be digested by the insect to cause infection. Entomopathogenic fungi (EPF) are possibly capable of acting synergistically with Bt to increase its efficacy against insect pests. Results The hypothesis of synergy or antagonism between Bt and EPF for the control of L. botrana was tested in two bioassays: A) Insects fed on Bt diet and subsequently some groups were sprayed by conidia of Beauveria bassiana or Paecilomyces fumosoroseus, and B) Grapes were sprayed by Bt, or B. bassiana, or combination of the two, and then untreated insects were placed to feed on the grapes. In both bioassays, combination treatments performed better than single treatments, indicating additive action or synergy. The Bt and B. bassiana combination treatment (Bt diet for 30 h and then sprayed with conidia of B. bassiana) resulted in 91% larval mortality while the single Bt and B. bassiana treatments caused 28% and 34% mortality respectively. Such results indicated synergism. Combination treatment on grapes also caused significantly higher mortality on L. botrana larvae, compared to single treatments. The median lethal time (LT50) was estimated as 8.43 days for the single Bt treatment, 7.87 days for the single B. bassiana treatment and 6.3 days for the combination Bt + B. bassiana treatment. Conclusions Absence of antagonism as well as additive action or synergy were indicated by the results. Larval populations of the pest can be effectively controlled by using microbial biocontrol agents. Further research is needed to investigate the biotic and abiotic factors that affect interactions between insect hosts and entomopathogenic organisms. However, the entomopathogens used in the present study showed remarkable action and may be included parallelly in control strategies against vineyard pests.

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Larval intraspecific competition for food in the European grapevine moth Lobesia botrana

Bulletin of Entomological Research ◽

10.1017/s0007485314000273 ◽

2014 ◽

Vol 104 (4) ◽

pp. 517-524 ◽

Cited By ~ 10

Author(s):

D. Thiéry ◽

K. Monceau ◽

J. Moreau

Keyword(s):

Life History ◽

Intraspecific Competition ◽

Life History Traits ◽

Larval Mortality ◽

Lobesia Botrana ◽

Reproductive Capacity ◽

Strong Increase ◽

European Grapevine Moth ◽

Grapevine Moth ◽

Larval Crowding

AbstractEffective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

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Characterization of entomopathogenic fungi from vineyards in Argentina with potential as biological control agents against the European grapevine moth Lobesia botrana

BioControl ◽

10.1007/s10526-019-09955-z ◽

2019 ◽

Vol 64 (5) ◽

pp. 501-511 ◽

Cited By ~ 1

Author(s):

Rodrigo López Plantey ◽

Daciana Papura ◽

Carole Couture ◽

Denis Thiéry ◽

Pablo H. Pizzuolo ◽

...

Keyword(s):

Biological Control ◽

Entomopathogenic Fungi ◽

Lobesia Botrana ◽

Biological Control Agents ◽

European Grapevine Moth ◽

Grapevine Moth

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Grape variety affects larval performance and also female reproductive performance of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae)

Bulletin of Entomological Research ◽

10.1079/ber2005417 ◽

2006 ◽

Vol 96 (2) ◽

pp. 205-212 ◽

Cited By ~ 54

Author(s):

J. Moreau ◽

B. Benrey ◽

D. Thiéry

Keyword(s):

Host Plant ◽

Adult Emergence ◽

Lobesia Botrana ◽

Larval Performance ◽

European Grapevine Moth ◽

Wild Grape ◽

Larval Host ◽

Fitness Index ◽

Grapevine Moth

AbstractFor insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.

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