Articles
The larval stage of the species Leptinotarsa decemlineata Say contributions to the study of ontogenetic development, in the northern part of the country
Article number
1391_58
Pages
421 – 430
Language
English
Abstract
The objective of these studies is the impact of some meteorological factors on the appearance and development of the insect, how it influences its life cycle in the context of climate changes in recent decades.
In Suceava County, according to the biothermogram with breeding areas, we have regions in the plateau with two complete generations per year, submontane regions with only one generation per year and no generation in the mountain area where the Colorado beetle does not meet the favorable conditions for development.
Among the meteorological factors, the influence of temperature and humidity was primarily studied, because they decisively mark the appearance, the intensity of reproduction and the further development of the insect.
The amplitude of the duration of the larval stage was particularly high (15 days) in the larval stage of G1. Contrary to this, in G2 the highest homogeneity was registered, the amplitude between years being only five days.
Very high amounts of precipitation in 2017 (192 mm), 2019 (118 mm) and 163 mm in 2020, distributed in 9-11 rains, associated with average temperatures of 14.4°C in 2017, 16.4-16,9°C in the years 2019 and 2020, were the causes that determined the extension of the duration of the larval stage at G1 up to 29-30 days in the years 2017 and 2020, and up to 34 days in the year 2019. Compared to the main years, in the year 2018. larvara in G1 it was 19 days, as a result of an optimal thermal regime (19.4°C) and a rainfall regime totaling 36 mm distributed over five days.
Compared to the first generation, larval development in G2 benefited from favorable conditions average air temperatures above 19.2°C and moderate quantitative precipitation in the years 2018-2020 (19-67 mm), but also very important (137 mm) in 2017. Under these favorable circumstances the duration of the G2 stage was 18 days in 2018, 20 days in 2017 and 22-23 days in 2020 and 2019.
In Suceava County, according to the biothermogram with breeding areas, we have regions in the plateau with two complete generations per year, submontane regions with only one generation per year and no generation in the mountain area where the Colorado beetle does not meet the favorable conditions for development.
Among the meteorological factors, the influence of temperature and humidity was primarily studied, because they decisively mark the appearance, the intensity of reproduction and the further development of the insect.
The amplitude of the duration of the larval stage was particularly high (15 days) in the larval stage of G1. Contrary to this, in G2 the highest homogeneity was registered, the amplitude between years being only five days.
Very high amounts of precipitation in 2017 (192 mm), 2019 (118 mm) and 163 mm in 2020, distributed in 9-11 rains, associated with average temperatures of 14.4°C in 2017, 16.4-16,9°C in the years 2019 and 2020, were the causes that determined the extension of the duration of the larval stage at G1 up to 29-30 days in the years 2017 and 2020, and up to 34 days in the year 2019. Compared to the main years, in the year 2018. larvara in G1 it was 19 days, as a result of an optimal thermal regime (19.4°C) and a rainfall regime totaling 36 mm distributed over five days.
Compared to the first generation, larval development in G2 benefited from favorable conditions average air temperatures above 19.2°C and moderate quantitative precipitation in the years 2018-2020 (19-67 mm), but also very important (137 mm) in 2017. Under these favorable circumstances the duration of the G2 stage was 18 days in 2018, 20 days in 2017 and 22-23 days in 2020 and 2019.
Authors
I.C. Enea, N. Negruseri
Keywords
climatic changes, humidity, temperature, larval stage, generations
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