Classical and augmentative biological control against ... - IOBC-WPRS

Giorgini
Data reported in Appendix 8 were summarized in Table 6, Table 7, Table 8, Figure 4 and
Figure 5. A list of the biocontrol agents used in augmentative biological control in grapevine is
reported in Table 6 and Figure 4. A list of groups and species of the targeted pests and the
antagonists used for their control is reported in Table 7 and Figure 5; the efficacy of biocontrol
agents is reported in Table 8.
The group of pests on which the highest number of researches on augmentative biocontrol has
been carried out is Lepidoptera (60% of total references) with the family Tortricidae representing
the main target (55%) (Figure 5) including the grape berry moths key pests Lobesia botrana and
Eupecilia ambiguella (Table 7). Bacillus thuringiensis has resulted the most frequently used
biocontrol agent against Lepidoptera by achieving an effective control of different targets in
different geographic areas (Table 7, Table 8, Appendix 8.7). We sorted 28 references (39% of the
total citations) dealing with the use of B. thuringiensis of which 23 references were referred to the
control of L. botrana. The augmentation of egg parasitoids of the genus Trichogramma
(Hymenoptera: Trichogrammatidae) resulted the alternative strategy to B. thuringiensis to control
Lepidoptera Tortricidae (13 references, 16% of total citations) (Table 7, Table 8). Field evaluations
indicated T. evanescens as a promising biocontrol agent of L. botrana (El-Wakeil et al., 2008 in
Appendix 8.1).
Fewer researches were carried out on augmentative biocontrol of other group of pests. First in
the list were mealybugs (Hemiptera: Pseudococcidae) (9 references, 13% of the total citations). In
field evaluations (4 papers) parasitoid wasps of the family Encyrtidae have resulted extremely
active and promising to be used in augmentative biocontrol of mealybugs (Appendix 8.2).
Antagonists used in augmentative biocontrol in grapevine were mainly represented by insect
pathogens (59% of the total citations), including the bacterium B. thuringiensis, fungi and
nematodes (Figure 4, Table 6). Beside the efficacy of B. thuringiensis, promising results were
obtained from researches in the control of the grape phylloxera Daktulosphaira vitifolie, a gallforming
aphid, by soil treatments with the fungus Metarhizium anisopliae (Table 8, Appendix 8.5).
Once controlled by grafting European grape cultivars onto resistant rootstocks, the grape phylloxera
has gone to resurgence in commercial vineyards worldwide and new biological control strategy
could be necessary to complement the use of resistant rootstocks and to avoid the distribution of
chemical insecticides in the soil.
Entomophagous arthropods, including parasitoid wasps and predators represented 41% of the
total citations (Figure 4, Table 6). Best results were obtained from researches on parasitoids (18
references), namely the use of Trichogrammatidae and Encyrtidae in augmentative biocontrol of
grape moths (Tortricidae) and mealybugs (Pseudococcidae) respectively (Table 7, Table 8,
Appendix 8.1 and 8.2). Among predators, augmentation of Phytoseiidae mites has produced some
positive results in controlling spider mites and eriophyid mites on grape (Table 7, Table 8,
Appendix 8.3).
Brief considerations
Key pests of grapevine like L. botrana and E. ambiguella can be controlled effectively with
augmentative strategies that rely on the use of B. thuringiensis. To date, formulations of B.
thuringiensis are currently used in IPM strategies. The specificity of B. thuringiensis could be a
problem in those vineyards where other pests can reach the status of economically importance, if
not controlled by indigenous and/or introduced natural enemies. Researches on augmentative
biocontrol should be implemented in order to develop new strategies to solve problems related to
emerging pests and alternatives to B. thuringiensis if resistant strains should appear in target
species.
References
Due to their high number, the references for this chapter are presented in Appendix 8.
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