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Correlation dependence populations abundance Сoccinella septempunctata L. and sucking pests of cereal crops
The article considers biological methods control pests of cereal crops. Analysis of the literature made it possible to conclude that the most effective use of coctsynelid is achieved in the fight against sucking pests of cereal crops and sugar beet. The most active among them are Сoccinella septempunctata L., Agony variegata Goeze. and Adonia bipunctata L. Larvae of еntomophagous two or three weeks, destroy about a thousand individuals of aphids and imago - every day 100 larvae and adults of aphids.
Main ways application entomophags against pests include: seasonal colonization, introduction and acclimatization, internally areal resettlement, creation of conditions for their reproduction.
Research of species diversity of sucking pests of crops (winter wheat and barley) was performed on 4 test plots (2.5 ha each) farm "Bronne", located on the territory Bereznovsky region of Rivne region. Accounting pests was carried out on the territory with a total area of 10 ha squares method.
To increase the population size of ladybugs we used their seasonal colonization. Seasonal colonization provides for massive artificial breeding and release of entomophagous in nature. Populations of еntomophagous are often in small amounts and cannot restrain reproduction of the pest. Mass release of insects is carried out in the early phase, damaged entomophages. In the future they will be expected to reproduce themselves.
Investigating pests of crops, we determined the degree occupancies for six-point scale according to the method Omelyuty V.P. In the phase of milk ripeness of winter crops we conducted census of cereal aphids, counting on their ears, looking into each field of 100 stems. Analysis of the results accounting made it possible to determine the average population of aphids varies from 0 to 3 points, and the average is 1.5 points. The most common areas for a large accounting cereal aphids - 27% of plants affected by this pest. Least distribution characteristic for barley aphids - 9% of plants affected.
Simultaneously, we conducted a study of species diversity of ladybirds. The results showed that among populations Coccinellidae, dominated Сoccinella septempunctata L. - 38% of all koktsynelid - an average of 24 imago at 100 waft of a butterfly net. Natural populations of entomophagous was not enough to deter the reproduction of aphids.
Plots of winter crops affected by aphids, colonized by larvae Сoccinella septempunctata. Land area of 1 m2 with plants winter crops affected by sucking pests settled larvae Сoccinella septempunctata and over time determine the degree occupancies of pest of areas, while comparing the results of the control area.
Results reflect the dependence between number of large cereal aphids and number of koktsynelid. It is proved the efficiency of using Сoccinella septempunctata L. in the fight with a lot of cereal aphids provided the density of larvae ladybugs at least 10 individuals per plant. Correlation dependence between the number of large populations of cereal aphids and larvae of Сoccinella septempunctata L. is already evident on the 5th day of the experiment. In particular, inappropriate to use insecticides against the pest in the degree of colonization 1 point and density of 10 larvae Сoccinella septempunctata per plant. If the degree colonization of large cereal aphids 2-3 points, and the density koktsynelid least 15 larvae per plant, then there is a complete destruction of the pest еntomophages already through three days.
Colonization of Сoccinella septempunctata L. density of 5 larvae per plant was not effective. Note that the experiment not taken into consideration the activities of natural populations of imago and larvae of Сoccinella septempunctata.
The results can be used in the development of technologies for growing organic agricultural products.
Key words: cereal crops, sucking pests, entomophages, Сoccinella septempunctata L.
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