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Vliv potravy na vývoj chrousta maďalového (Melolontha hippocastani Fabr.)
Čech, Petr
This thesis defined impact of insect species on forest and landscape in broader context and described possible impacts of their gradations on forests in the central Europe in connection with pest species, its food preferences, overpopulation occurrence and local conditions. The research evaluated food requirements of Forest Chockchafer (Melolontha hippocastani Fabricius, 1801) and food-connected impact on fertility, food preference and caused damage. The theses also determined the influence of food (Quercus petraea (Matt.) Liebl.) treated with manganese chloride solutions in three concentrations on food consumption, time of adult activity and fertility of adult specimens of Forest Chockchafer. It was necessary to use laboratory breeding to get desired data. After feeding on the oak, the Forest Chockchafer was in the best condition in terms of monitored parameters and the ability of survival on pine blossoms was proven. Reaction of Forest Chockchafer on increased amount of manganese was negative and manganese had also influence on its activity, ecology and physiology. Despite its defence mechanisms - excretion of manganese (up to 24 110 mg.kg-1) in the material of excrement and integration to its own body parts not participating on its physiology processes (up to 430 mg.kg-1) - impact on Forest Chockchafer adults was shown by shorter feeding period (by eight and a half day for female specimens), decreased food intake (down to one fifth) and reduced fertility. While in the case of treatment T1 the fertility was reduced down to one fourth, with manganese concentration in the diet 17 700 mg.kg-1 (treatment T3) female specimens were not able to lay eggs at all. The toxicity limit for Forest Chockchafer was exceeded and female fertility was reduced.
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Hospodářský význam chrousta Melolontha hippocastani F. v gradačním území LS Strážnice
Opavský, Tomáš
The aim of this work was to assess the presence of the chestnut cockchafer in LS Strážnice, primarily on the Vracov and Bzenec areas. Using the soil probes the etiology and abundance of the grubs in the soil profile were examined. The current population density of the chestnut cockchafer in this area has been compared with historical damage. Based on the evaluation of health status of the seedlings, the damage caused on planting in the Bzenec area from 2013 and 2014 was evaluated financially. In older cultures of the age 5-10 years, the ability to regenerate trees after being infested by grubs was evaluated. The course and the intensity of swarming were evaluated by light traps. Climatic conditions were scanned via usage of meteorological stations. The ovaries of the deceased females were examined by autopsy. Selection of the laying place of the females was analyzed from the historical materials. The results of the work proved that there is an ever-increasing population of Melolontha hippocastani F. in area of LS Strážnice. Economic loss on planting in the Bzenec area in the years 2013-2014 exceeded 2.5 million Czech crowns. At a time when roots are not eat by grubs, slightly damaged pine trees can regenerate. The number of captured imagos in the Vracov area exceeded all quantity recorded in previous years. The first eggs ready for laying appeared on females on May 6, 2015. The selection of the oviposition site of the females was evaluated with the preference of laying in the old stands.
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Faktory ovlivňující obnovu lesa na požářišti u Bzence (LS Strážnice)
Jarošová, Veronika
The aim of this bachelor thesis was to determine the current status of the population of beetle maďalového in the area of fire residues in the forest governance of Bzenec Strážnice and its surroundings. A fire broke out at the end of May 2012 and damaged the area of almost 165 ha of forest. First instar grubs, which were present in soil of burnt vegetation at the time, were not hit by the fire, and then these grubs caused enormous loss of spring planting in 2013. The soil of fire residues was tested with various methods of soil preparation, which would lead to reduction of the amount of beetle grubs maďalového. Out of these methods, the method of soil preparation with milling cutter with depth effect was the most effective one. Application of FORCE 1,5g insecticide had positive effect on the survival of planted seedlings. The dispersion of grubs, in the stand depending on the distance from the tree trunk and the amount of grubs depending on the age of original vegetation, had been investigated. The results showed that the grubs do not have a single concentration but are scattered along the stand depending on the root system, and they were mostly present in the stands of the second class.
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Chroust maďalový (Melolontha hippocastani F.) – hospodářský význam a možnosti eliminace škod v gradačním území LS Strážnice
Opavský, Tomáš
The aim of this work was to evaluate the amount of damage caused by the grubs of forest cockchafer. The damage was assessed in relation to the habitat conditions of the mining and cultivation practices. The pilot plant treatment of Actara 25 WG and Force 1.5 G was evaluated for efficacy against 2nd and 3rd grub instars. A methodical design of aerial intervention to inhibit the forest cockchafer during the 2019 swarming was drawn up. When evaluating the amount of damage, 59,233 pieces of seedlings were checked in 2017. The pilot plant treatment was applied to 4 473 pieces of seedlings and the application was carried out in seven different variants on three districts of the Forestry Administration in Strážnice. The average amount of damage caused by the infestation of forest cockchafer grubs in the Forestry Administration in 2016–2018 is 36%. The Actara 25 WG applied by irrigation was evaluated as the most efficient variant during pilot plant treatment. Based on the vegetation inspection and the extent of the damaged area, an aerial intervention was proposed in two variants to inhibit the forest cockchafer swarming in 2019.
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Ochrana lesa před chroustem maďalovým v gradačním území Moravské Sahary
Jarošová, Veronika
The aim of this master´s thesis was the evaluation of options that should lead to the elimination of the harmful effects of the white grubs of Melolontha hippocastani to the gradational area of Moravian Sahara (part of forest maintenance LS Stážnice, the Bzenec district). The effectiveness of chosen preparations (Force 1,5 G and Actara 25 WP) on the white grubs of Melolontha hippocastani was observed and conducted under controlled conditions in the ´container experiment´ with 380 seedlings of Pinus sylvestris. This experiment was repeatedly conducted five times over a period of 3 years. The results show that the most effective preparation against the white grubs is Actara 25 WG (200 up to 400 g/ha/600 l water) in the form of watering. This preparation in the form of spraying was ineffective. Inconsistent results were reached with the preparation Force 1,5 G. At the same time, the vertical movements of white grubs during their development stages in the soil were being observed over the period of 2015–2018. This observation took place in the drill holes of the following proportions 50 x 50 x 60–140 cm. The results confirmed that the depth of wintering of the white grubs and their movements during their vegetative state depends on the soil´s temperature and moisture, and the available sources of food to the current instar of the white grub.
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The reaction of phytophagous on differenced manganese content in the diet
Martinek, Petr
The rapid adaptation of insect species on environment changes can represent a significant advantage for their development and consequently a great negative effect for the stability of forest ecosystems. Larval individuals of Cabera pusaria and Lymantria dispar and adults of Melolontha hippocastani and Phillobius arborator is in general widely expanded species of herbivorous insects in European regions and with them are connected huge economic and ecological losses. The composition of food (biogenic elements, trace elements, heavy metals, proteins, carbohydrates etc.) is the main parameter of food quality. Laboratory experiment with natural diet (assimilation apparatus of Quercus petraea and Betula pendula) in control conditions (temperature, humidity, and light) were used for determination of insects’ reactions to increased concentration of manganese in the diet. Food was contaminated by soaking in solutions of MnCl2.4H2O with graded manganese concentrations. On the base of experiment design and character of reared experimental species we determined the food consumption, the activity period of adults, the mortality of larvae, the quantity of eggs laying, the dry mass and live weight of experimental individuals, concentrations of manganese in unconsumed food, excrement and lyophilized bodies, larval and pupal exuviae. Mentioned parameters were observed for determination of reactions of experimental insect species on changed food quality via the presence of high manganese contents. The results showed, that the reactions of individual experimental animals were very different. We observed the negative reaction to high manganese content in the diet of L. dispar larvae with the tendency of its compensation (the increasing food consumption rate and prolongation of development). Caterpillars of C. pusaria were very sensitive to changed food quality and therefore we observed high mortality. On the other side, the high manganese content in the diet of P. arborator in the laboratory conditions influenced neither their food intake nor their mortality. For individuals of M. hippocastani very high content of manganese in the diet significantly influenced the food consumption and thereby their development(distortion of copulation and consequent eggs laying). We observed the repellent effect of high levels of manganese in the diet. In all cases, the elimination mechanisms of surplus manganese in the diet were observed. Individuals in experiments exuded manganese through the digestive system into excrements and by incorporation of it into unspecified parts of their adult body without direct physiology activity or in exuviae of caterpillars.
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