Potatoes should be protected from pests and Colorado beetles throughout the season. Measures and control measures include both special arable farming techniques and chemical agents used to treat planting tubers and seedlings.
COLORADO BEETLE PEST
At present, the Colorado beetle pest is distributed throughout Russia everywhere. Beetles and larvae are harmed by coarsely eating leaves, petioles and even stems, from sprouting to harvesting.
The greatest damage is caused by the Colorado beetle on those sites where it is too late to plant potatoes, i.e. the pest, “unwillingly”, appears on the plants too “early” in the phenophases.
Also, the damage from the beetle and its larvae are very noticeable both in areas with sparse plantings and in areas where there is a low agrophone. Almost everywhere bushes are eaten by this pest completely, which results in high yield losses.
Beetles winter in the soil at the depth of arable horizon – up to 20-30 cm.
After the soil has warmed up to 14°C, they begin to emerge from the soil, but not simultaneously, but stretched out.
PROTECTING POTATOES FROM COLORADO BEETLES
Effective protection against the Colorado potato beetle begins with a careful harvest of the tubers in autumn. The beetles immediately infest self-seeding (already ascended plants from the unsupervised tubers in the autumn) plots of homestead lands, replanting, as well as plots close to last year’s fields and places of drilling. In remote areas, the pest appears 2-3 weeks later. Soon the females begin laying eggs, placing them in 20-30 eggs on the other side of the leaves. On average, the female lays 400-600 eggs, and some individuals lay up to 2400 eggs. After 7-10 days larvae appear from eggs, which live and harm 15-20 days, during this time they pass 4 ages. The timing of their appearance depends on weather conditions, but it usually happens in June.
After feeding, the larvae go into the soil for pupation, and after 10-15 days new beetles appear. Due to the length of time the beetles come out of their wintering grounds in the fields, one can often see both wintering beetles and new ones appearing at the same time. At this time, potatoes need special protection from the Colorado beetle.
Hot weather depresses the beetles, and some of the wintering beetles fall into the summer period of up to 30 days and more. Due to poor or no food, beetles may have a temporary suspension of activity for a longer period of time, and for this reason they are sometimes at rest in the soil for up to 3 years. With an average number of larvae and beetles on the field (20-40 larvae and beetles per bush), the leaves are usually halved and the yield is reduced by a factor of 2-3. When leaves are completely united, the yield is reduced by 10 times, and what remains will be substandard, will be of low quality and have poor haemorrhage capacity.
METHODS AND MEANS OF CONTROLLING THE COLORADO BEETLE
Control of the Colorado beetle should be carried out annually and in a timely manner (regardless of the appearance of the pest and its mass development):
Planting of varieties of later maturation dates – Sotka, Zarevo, Temp, etc., as well as varieties forming a powerful canopy – Addretta, Nikita, Shurminsky, etc;
Planting at an optimal early date on well-tightened soils, so that the plant “managed to escape” from the still “sleeping” beetle;
Repeated embedding of seedlings by 3-5 cm (the beetle does not chew them in the soil);
high hillification of shrubs with backfilling of lower leaves on which eggs are laid;
loosening of row-spacing 2-3 days after mass pupation of larvae;
Removal of the haulm before harvesting worsens the conditions for wintering;
Late and deep ploughing of fields (2-3 cm below the arable horizon) turns the beetles to the surface from under the potatoes, where they can then die of frost.
If larvae of 1-2 years of age appear, if they are more than 20 per bush and more than 20% of bushes are inhabited by them, it is recommended to carry out focal or continuous spraying with one of the chemical preparations, which include the following means of control of the Colorado beetle:
- Arrivo (cimbus, sherpa), 25% B.C. 1.5 ml per 10 liters of water, with a flow rate of 1-2 weaves;
- Summi-alpha, 5 % C.E. – 5 ml per 10 liters of water;
- decis, 2.5 % k.e. – 2 ml per 10 liters of water;
- kinmex, 5.0 % k.e. – 2.5 ml per 10 litres of water and other preparations permitted for use in small farms and private sector, but not more than two sprays.
- Biological preparations are available methods of control of the Colorado beetle, they operate more slowly, but they are safer for humans and the environment: bicola is a new form of bitoxybacillin, consumption is less than 20 g per 10 liters of water (instead of 30-50 g of bitoxybacillin); fitoverm, 0.2% of k.e. – 4 ml per 10 liters of water. Mixture of 0.2 % 4 ml + 10 g bicolours per 10 l of water, not inferior to decis
The first bio preparation treatment is carried out at the beginning of mass hatching of larvae, again after 7-8 days if more than 5 larvae are settled per bush. It has been noticed that Fitoverm also destroys beetles.