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

Chapter 6
Identified difficulties and conditions for field success of biocontrol.
2. Technical aspects: factors of efficacy
Michelina Ruocco 1 , Sheridan Woo 1,2 , Francesco Vinale 1 , Stefania Lanzuise 2 , Matteo Lorito 1,2
1 CNR-IPP, Consiglio Nazionale delle Ricerche, Istituto per la Protezione delle Piante, via
Università 133, 80055 Portici, Italy
2 Dip. Arboricoltura, Botanica e Patologia Vegetale, Università di Napoli Federico II, via
Università 100, 80055 Portici, Italy
Quality of the BCAs formulations
Numerous investigations on the development of biopesticides have been initiated as legislation and
government policy have demanded less reliance on chemical pesticides and greater adoption of
IPM. In Europe, some countries have set goals of reducing pesticide use by 50%. Successes have
been achieved through better timing of applications, so that lower dosages are effective and
substituting less hazardous and more active materials, to reduce the number of applications.
Biopesticides are distinguished from conventional chemical pesticides as many are very
selective and are non-toxic towards non-target organisms. While biopesticides are likely to be less
harmful to the environment than the conventional ones, care needs to be taken that wastage is
minimised, by selecting the most appropriate droplet spectrum. A disadvantage of biological agents
relative to chemicals, is that many are not sufficiently persistent and are relatively slow acting;
therefore, research has been directed at extending the period of activity. However, some such agents
may persist in the field or the forest for many months, and a risk–benefit analysis should be
performed to establish their environmental acceptability.
Transition from the optimised conditions of a laboratory experiment to the harsh conditions
experienced in the field has so far proved more difficult for application of biopesticides in contrast
to chemicals. This has undoubtedly been due to lack of investment in the development of effective
formulations and delivery systems, in order to commercialise more potential biopesticides. The
relatively small effort invested in target-specific sprayers, compared with the investment in
laboratory studies, has led to unbalanced development, and exemplifies the need for closer
integration between formulation and engineering research. The challenge is to get effective
formulations so that biological control agents can be easily applied by farmers.
A good example, the case of Trichoderma: direct and indirect mode of action against
plant pathogens
Trichoderma species have long been recognized as biological control agents (BCAs) for the control
of plant disease and for their ability to increase plant growth and development. They are widely
used in agriculture, and some of the most useful strains demonstrate a property known as
‘rhizosphere competence’, the ability to colonize and grow in association with plant roots (Harman
2000). Much of the known biology and many of the uses of these fungi have been documented
recently (Harman et al. 2004a; Kubicek et al. 1998; Perello et al. 2009). The taxonomy of this
fungal genus is continually being revised, and many new species are being described (Komon-
Zelazowska et al. 2007; Kubicek et al. 2008; Overton et al. 2006; Samuels 2006; Samuels and
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