Results of testing of selected pesticides against adults of apple blossom weevil at the beginning of the growing season
2019
Suran, Pavol | Fiala, Rostislav
Orchard consisting of 13 apple varieties grafted on rootstock M 9 has been carried out for 12 years, with an assessment of the influence the air temperature on the flower set, flowering time, fruit set and harvest. Pearson`s correlated coefficient was used to establish a relationship between climatic conditions and tree parameters. It was found a close relationship between flower set and sum of temperature in March and April of previous year (r = 0.443) and for sum of precipitation from May to the end of June of the previous year (r = 0.282). Start of flowering was in the closest relationship with a sum of precipitations from March to the end of April (r = 0.370) in given year. As fruit set as well harvest were affected by air temperatures between May till the end of August and by precipitations during flowering (March and April) as well. The correlation coefficient (r) of fruit set was r = 0.290 (temperature) and r = 0.620 (precipitation). For the harvest, a closer dependence on temperature and precipitations was defined, which corresponded to a correlation coefficient r = 0.511 and r = 0.534, respectively. Late spring frosts in 2007, 2011, 2012, 2014 and 2016 were a frequent phenomenon limiting the fruit harvest. The most varieties were damaged in 2011, when the average harvest was only 0.29 kg/tree. The average harvest over 12 years was set at 7.75 kg/tree. The values of harvest and other parameters have varied over the years, due to different climatic conditions in individual years. Important influence was evident in date of flowering the varieties, which differed up to 2 weeks yearon-year. It should be seen that the expected climate change has a future impact on apple production.
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