The effect of sustainable plant protection and apple tree management on fruit quality and yield

Recently, relatively large amounts of pesticides have been used to control diseases and pests in modern apple production. Our investigations were aimed to estimate the effects of sustainable plant protection system and integrated apple-growing technology on apple fruit quality. The research was carried out in 2011-2013 with apple cultivars 'Auksis', 'Alva', 'Connell Red', 'Ligol', 'Lodel', 'Rubin' and 'Sampion'. Sustainable plant protection system based on the internet supported forecasting system iMETOSrsm. According to the rules of the sustainable plant protection system, plant protection products with the same active ingredients were used not more than twice, and preharvest interval was 1.5 times longer than indicated on the product label. Plant protection products labelled as "very toxic" and "toxic" were not used. Scab susceptible cultivars 'Alva' and 'Ligol' on average were sprayed twelve times when other cultivars-nine times. Sustainable plant protection system did not guarantee total scab control; therefore, damaged fruits should be thinned manually. High-quality fruit yield was on average 39 t ha(-1), but the yield of 'Sampion' and 'Ligol' reached 51-56 t ha(-1). The 59% of all investigated cultivars fruits were 70-80 mm in diameter, and 30% of fruits. more than 85 mm. All tested cultivars had averaged low index of biennial bearing 0.11-0.34.