You are here
Harmfulness of cotton-boll worm and microboicontrol of its population on tomato plantings
The article provides analysis of information concerning dangerous tomato pest – cotton-boll worm Helicoverpa armigera Hb. It describes the pest morphology and biology and gives data on growth of harmful action duration due to widening of nutritive base, as well as efficiency of phytosanitary measures to limitation of population boom and decrease of its harmfulness under conditions of climate change, besides necessity of salanaceous cultures monitoring and effectiveness of biological preparations applying for tomato protection in South Ukraine environment is grounded.
The literature reveals mass reproduction and wide expansion of cotton worm not only in the Steppe zones of Ukraine but in the Forest steppe and partly in Polissya (forest area). It can be found only in cultivated lands but also in dry meadows, pastures in steppe and gills where it was found on weeds – solanum, stramonium, henbane, lucerne, doorweed, pigweed. Particular attention should be paid to the fixed fact of mass nutrition of the pest on common ragweed plants growing on waysides, borders of sunflower seeds and stubble fields of winter wheat.
Significant harm to tomatoes can be caused by disorder in crop rotation and their dropping after highly damaged crops as well as after solanaceae. In such cases and also on highly foul fields overwintered pests can damage up to 70 % of solanberries and in some individual years – almost whole tomato harvest. During vegetation period it develops in 2-3 generations, actively colonizes plants at starting of blossom, solanberries formation and goes on feeding on ripening berries up to harvest works completion.
The study aimed to do the pest surveillance of phytosanitary condition of tomato crop growing in the open, new pesticides testing in pest control and validation of ecological measures for tomato protection.
It was experimentally found out that the pest prefers irrigation fields and damages mainly generative shoots and ripening solanberries. Coton-boll worms of first age feed on tomato leaves, damage character is skeletization, as well as those of second and third ages mostly eat out parenchyme of generative shoots. Eldery spicular worms do great harm to tomatoes by eating out holes near tomato handle and filling them with rottenness.
Due to temperature climatic conditions of Odessa region first flight of second generation butterflies takes place at the end of June and makes 12 numbers/trap, with its peak of the third generation at the end of July/August having higher flight activity – 16 numbers/trap during 7 days.
We conducted a field test of the efficiency of some biological control preparations such as Actophyte (3,0 and 4,0 l/ha), Gaupsine (6,0 and 8,0 l/ha), Trihopsine (8,0 and 10,0 l/ha), Becimide (4,0 and 6,0 l/ha). The preparations were used in two terms – June15 and July 5 at blossom and solanberry growening.
Performed study and registrations showed that technical efficiency of biopreparations used varied between 69-75 %. According to results of marked incectofungicides testing in fight against cotton-boll worm second generation the best entomopathogenic activity was detected while application of preparation Gaupsine at the insecticide rate of 8,0 l/ha, whose technical effectiveness made 74,9 % to the 14-th day of registering.
Much smaller effectiveness was detected at preparation Actophyte at the insecticide rate of 4,0 l/ha it was 72 %, the two other applied biopreparations (Trihopsine and Becimide) provided pest population control at the level of 65-69% as compared to control. In future it is necessary to work through reasonable incectofungicide rates, as well as optimal terms and frequency of their application.
Key words: tomatoes, cotton-boll worm, polyphage, population, control measures.
Attachment | Size |
---|---|
![]() | 661.17 KB |