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To achieve an effective reduction of the damage by root feeding grubs of Melolontha spp. in organic strawberry plantations, we have tested an approach targeting different stages of the insect’s biological cycle. Adult beetles were caught by using light traps or by manual shaking off trees associated to the monitoring of cockchafer swarm flights supported by forecasts models. Phytosanitary pre-crops and the application of biological control agents were tested against the larvae. The three predictive models utilized to forecast the period of emergence of the cockchafer were suitable to support the deployment of the light traps before the adults’ swarm flights. Traps positioned at 4-m height were more effective in attracting the beetles than those kept at 2-m height. Buckwheat in mixtures with either a mustard or leguminous species used as pre-crops was able to reduce the population of grubs, and considering also its capacity in solubilizing recalcitrant phosphorous sources should enter in a rotation with strawberry or any other crop susceptible to grubs damage. The distribution of two different strains of entomopathogenic fungi resulted in a reduction of the damage to plants due to the cockchafer grubs’ activity, even though the efficacy resulted to be dependent on environmental and agronomic factors, including the kind of formulation used. It is concluded that to assure a sufficient level of control of Melolontha spp. in organic strawberry plantations, it is necessary to integrate several methods that are targeting the different biological stages of the insect and are based on different kinds of practices.

BACKGROUND: The Strawberry is an economically important crop in Poland. However, the production of strawberries is difficult and costly, as pests and pathogens causing diseases often damage plants. The strawberry mite - Phytonemus pallidus (Banks) is the most dangerous among pests and one of the most difficult to control. In the past, active substances such as Endosulfan, Amitraz and Propargite, were used to control the pest but they have been withdrawn from the pest control program a few years ago. OBJECTIVE: The intention of this study was to evaluate the efficacy of Abamectin and fungus Beauveria bassiana to control the strawberry mite on strawberry plants in the open field, as well as the susceptibility of selected strawberry varieties and genotypes to the pest. METHODS CONTROL EXPERIMENTS: Studies were performed on ‘Honeoye’ plants. Naturalis (Beauveria basiana )a t a dose of 1.0–1.5 l/ha+adjuvant Protector (pine resins) at a dose of 0.3 l/ha, Naturalis – 1.0 l/ha+TerraSorb ® Complex SB ( – amino acids, biostimulants) – 1.5 l/ha (2013) and Vertimec 018 EC (abamectin) at a dose of 1.0 l/ha were estimated. The population of strawberry mite was notated both before, and after the application of the tested products. SUSCEPTIBILITY OF CULTIVARS: The observations of the strawberry mite presence on the strawberry cultivars, were carried out in years 2012–2013 on an experimental cultivar trial plantation. The population of the pest was counted on strawberry leaves, taken from plants of different varieties and genotypes. RESULTS: Vertimec 018 EC showed good efficacy in the control of the strawberry mite, but the long-lasting effect was observed only following two applications of the product. Naturalis (Beauveria bassiana)+Protector proved to be more effective than the treatment of Naturalis+TerraSorb ® Complex, however the pest control was poorer and of short duration than after application of Vertimec 018 EC. CONCLUSIONS: In experiments carried out in the open field Abamectin proved to be more effective than Naturalis. Some strawberry varieties such as ‘Dukat’, ‘Flair’, ‘Real’, ‘Salut’, ‘Vima Rina’, ‘Malling Pearl’ were not infested by to strawberry mite - the pest specimens were not observed on experimental plots within two years of this experiment. A high population of the strawberry mite was noted on strawberry cultivars such as ‘Evita’, ‘Hokent’, ‘Albion’, ‘Feriusz’, ‘Honeoye’ and ‘Karel’.

The use of entomopathogenic fungi for biocontrol of plant pests is recently receiving an increased interest due to the need of reducing the impact of agricultural practices on the environment. Biocontrol efficacy could be improved by co-inoculation of different microorganisms. However, interactions between the fungal species can trigger or depress the biocontrol activity. Co-inoculation of two entomopathogenic fungi (Beauveria bassiana and B. brongniartii) was performed in vitro to evaluate the effects of their joint behaviour on a range of different carbon sources in comparison to single inoculation. The two species showed a very different metabolic profile by Phenotype MicroArrayTM. B. bassiana showed a broader metabolism than B. brongniartii on a range of substrates. B. brongniartii showed a greater specificity in substrate utilization. Several carbon sources (L-Asparagine, L-Aspartic Acid, L- Glutamic Acid, m- Erythritol, D-Melezitose, D-Sorbitol) triggered the fungal metabolism in the co-inoculum. SSR markers and Real Time qPCR analysis showed that different substrates promoted either the growth of one or the other species, suggesting a form of interaction between the two fungi, related to their different ecological niches. The methodological approach that combines Phenotype MicroArrayTM and SSR genotyping appeared useful to assess the performance and potential competition of co-inoculated entomopathogenic fungi.

The application of biological control agents (BCAs) is considered as an effective alternative for pest control. However, factors such as the formulation of the product, whose quality can affect the inoculant viability and persistence in soil, the stabilisation of the biocontrol effect under field conditions and the influence of agronomical practices as well as of the environmental conditions (weather and soil) are hampering a wider use of BCAs. After a brief review of these factors, we present some results concerning agronomical and ecological aspects from a case study carried out using different entomopathogenic fungi on organic strawberry plantations, which underline the possibility of improving BCAs efficacy, particularly when integrated into a more general strategy of pest control.

The effectiveness of spirotetramat in the control of pear psylla (Cacopsylla pyri) on pear trees was investigated in five field experiments, carried out in years 2009- 2011. One or two treatments were applied in June; the first treatment in the early stage of larvae hatching from eggs deposited by females from the summer generation, whilst the second application was carried out about two weeks later. In all the experiments, spirotetramat as Movento 100 SC applied at a dose of 2.25 l/ha effectively reduced the pest population after only a single application (total reduction of larvae after one week post-treatment 75.3-91.4%, and 83.7-97.6% at two weeks posttreatment). Movento 100 SC applied after a single application at a lower dose of 1.8 l/ha had a slightly worse effect (the total reduction of larvae at one week posttreatment was at the level of 58.4-91.3%, and two weeks after application at the level of 56-92.6%) - but in this case only a few larvae at stages L4 and L5 were found on pear shoots. The effectiveness of spirotetramat at both doses after two applications was very high. In comparison with standard insecticides the efficacy of spirotetramat was higher or not significantly different. In two experiments the application of standard compounds such as diflubenzuron and novaluron was not effective in controlling pear psylla and therefore did not prevent damage to pear trees. This may suggest that local populations of the pest are resistant to these measures, especially since they have been used for many years to control other pests of pear trees

Summary The blackcurrant gall mite (big bud mite) – Cecidophyopsis ribis (Westw.) is the most dangerous pest of blackcurrant in many countries. C. ribis is a key pest in Poland and causes severe damage on some plantations, destroying even more than 50% of the buds. The big bud mite infests most of the commonly grown cultivars and only a few are resistant. Looking for new possibilities to control the pest is still necessary. The experiments were carried out at the Research Institute of Horticulture in 2008–2011. Fenpyroximate active substance in Ortus 05 SC showed high effectiveness in reducing the number of the blackcurrant gall mites emerging from treated buds. Ortus 05 SC (1.25; 1.5 l/ha) and Ortus 05 SC (1.5 l/ha) + Slippa (0.1 l/ha) applied 3 times during migration of the big bud mite, reduced the number of damaged buds by 76–90% compared to the control bush. Also Ortus 05 SC (1.5 l/ha), applied twice: at the beginning and during the full blossom of black currant significantly reduced the number of buds infested by the big bud mite. On the bushes where Ortus 05 SC (1.5 l/ha) + Slippa (0.1 l/ha) were used twice, slightly less damaged buds compared with the treatments without wetting were reported, but the differences were not statistically significant.