Integrated methods for protecting crops from diseases, pests, and weeds

Four methods of crop protection

To ensure reliable crop protection against weeds, diseases, and pests, four interrelated methods are used in practice. The agrotechnical method is fundamental: it includes the introduction of scientifically sound crop rotation, proper tillage, balanced nutrition for crops, and the selection of resistant cultivars. The biological method helps control the number of harmful objects with the help of their natural enemies and biological products. The physical method is based on the influence of temperature regimes and physical fields — for example, pea weevil larvae in pea grain are destroyed by simple freezing. The most common remains the chemical method, which involves treatment with pesticides, as well as the use of defoliants and desiccants to facilitate harvesting.

In a biological protection system, it is important for an agronomist to correctly use pheromone traps and entomophages. Synthetic rubber-based traps are active for 2–3 months and allow for timely detection of the beginning of pest flight. To combat harmful Lepidoptera, Trichogramma — a parasitic insect that destroys pest eggs — is released into the fields. The Trichogramma biomaterial is supplied in the form of a loose mass of Sitotroga eggs containing pupae or adults (1 cubic cm weighs about 0.5 g and contains 80,000 individuals). The release of entomophages is carried out at an air temperature of 14 to 28 °C and a wind speed not exceeding 5 m/s using aircraft or hang gliders.

1. Hang pheromone traps in the orchard at the beginning of flowering (in the middle of the canopy at the ends of the branches at a rate of 1 trap per 1.5 hectares).
2. Carry out regular counts of trapped moths every five days.
3. Carry out treatment against the first generation of codling moth when 5 moths are caught per week.
4. For subsequent generations, start treatments when 3 moths are caught per week.

Treatment regulations and seed treatment methods

The effectiveness of chemical treatments directly depends on strict adherence to agrotechnical deadlines and the correct setup of spraying equipment. Machines must guarantee uniform distribution of the working solution over the entire area of the field. Any serious deviations from the application rate of the preparation or unevenness of the spray pattern reduce the profitability of treatments and can cause crop burns.

In practice, chemical and biological protection methods include the following measures:

• Pre-sowing seed treatment.
• Spraying and dusting of plants during the growing season and soil.
• Aerosol treatment of plants, storage facilities, and greenhouses.
• Fumigation of plants, soil, warehouses, and seed material.
• Placement of poisoned baits.
• Use of pheromone traps.
• Use of entomophages.

Four main technological approaches are used for seed preparation. The dry method of mixing with a powdered preparation is simple and economical, but the active ingredient is poorly retained on the grain. The labor-intensive wet method requires moistening with a formalin solution followed by sweating under a tarpaulin and drying. The thermal method with immersion of seeds in water heated to 50 °C is technically complex but effectively destroys loose smut of cereals. The fine-dispersion method with the application of a pesticide suspension ensures optimal coverage and retention of the preparation on the surface.

• Trichogramma release density — 10–150 units/m²
• Air temperature for releasing entomophages — 14–28 °C
• Permissible wind speed for spraying — up to 5 m/s
• Permissible wind speed for dusting (at temps. up to 25 °C) — up to 3 m/s
• Water temperature for thermal seed treatment — 50 °C
• Water consumption for fine-dispersion treatment — 8–10 l/t