When growing asparagus, both in the open field and in greenhouse conditions, you should be prepared for the occurrence of diseases and insect pests. Their timely recognition and appropriate measures will help preserve the harvest.
Asparagus diseases
Most of the diseases of asparagus are fungal diseases that cause plant spotting. Their source is waterlogging, weeds and weather conditions. But among the ailments there are also viral diseases, which are carried by insects.
Fusarium
The causative agent of this disease is the fungus Fusarium Link. The disease is manifested by the appearance in June on the root part of plants of brown or wine spots with a light, fluffy bloom. The culture turns yellow, has a weakened appearance and dries up. The disease is focal in nature, since it is quickly transmitted from diseased asparagus to healthy.
Affected asparagus quickly dies due to the destruction of the stem and root system. Most often, waterlogged crop beds and thickened plantings are at risk. The fungus prefers to develop in already mature areas of asparagus.
Control and prevention measures involve:
- thinning of asparagus plantings;
- shallow planting of seedlings and seeds;
- adjustable humidification;
- fungicidal treatment of soil and planting material.
Rust
Fungal disease. In early May, light, prominent spots appear on young asparagus stems. As the spores mature, the mycelium darkens. Ultimately, its color takes on a red-orange hue, reminiscent of rust.
The fungus loves warm, humid weather. It is spread by precipitation, irrigation and wind. Rust spores overwinter on the remains of asparagus and weeds.
The disease, developing annually in the same place, strengthens its position, dispersing spores everywhere. Asparagus yields drop every year, eventually approaching zero.
Prevention and control methods are reduced to:
- weed control;
- maintaining a distance of 300-400 m between young and old asparagus areas;
- removing and burning affected asparagus;
- preparation of soil and seeds for planting using disinfection methods.
Fomoz
A fungal disease caused by the fungus Phoma asparagina Tehon et Stout. When infected, brownish-brown spots of irregular shape with a bright border appear on asparagus. When the spores mature, black blotches can be seen inside the lesions. Asparagus stalks affected by phomosis stop growing and gradually dry out. The yield drops sharply.
Particularly suitable conditions for the spread of the disease are cool and rainy weather, as well as waterlogging of the soil as a result of improper watering.
To prevent phomosis of asparagus it is recommended:
- carefully remove plant residues before digging up the site;
- burn plants affected by the fungus;
- observe crop rotation;
- carry out antifungal treatments.
Cercosporosis
The causative agent of the disease is Cercospora asporagi Sacc. Affected asparagus is covered with small oval spots up to 0.4 cm in size. A light-colored spot with a gray coating. The wide edging of the affected areas is bright red.
Diseased plants wither quickly, and the yield drops sharply.
Precipitation and windy weather are favorable conditions for the spread of fungal spores.
Preventive methods and measures to combat cercosporosis are reduced to:
- killing infected asparagus;
- competent and timely agricultural technology;
- observance of the order of planting crops;
- antifungal treatment.
Mosaic
A viral infection caused by the Asparagus mosaic virus. The disease is manifested by the appearance of a yellow spot on asparagus, from which the palatability deteriorates, and the amount of the harvested crop decreases.
Spread the asparagus mosaic of the aphid colony. During wintering, the virus remains unharmed in crop residues.
To combat a viral infection and prevent its appearance, you should:
- to process asparagus and surrounding crops with aphid remedies;
- take into account the proximity of plants;
- observe crop rotation;
- destroy weeds.
Root rot
A fungal disease that affects the root system of asparagus. When infected with a fungus, the plant stops developing due to a lack of nutrients that cannot be absorbed by the root. It becomes hollow on the inside, on the outside it is covered with a dark putrid formation.
Root rot is especially widespread with abundant watering and precipitation.
It is almost impossible to save plants with foliar treatments. Infection can be avoided only with dressing and antifungal treatment of soil and seed, observing crop rotation when choosing a planting site.
Red rot
The disease is caused by the fungus Rhizoctoma violacea Tul. When infected, gray spots are visible on the root of the asparagus and roots. Ripening, they become covered with a purple-purple bloom. Asparagus affected by red rot stops developing and dies.
The fungus develops and spreads in high humidity and warm weather conditions. Overwinters in an inactive form on plant debris.
To combat red rot, you must take the following measures:
- when choosing a landing site, give preference to areas on heights where groundwater is at a great distance from the surface and the wind has the ability to blow through the landing;
- observe moderate watering, and loosen the soil to avoid crusting on the surface;
- clean the garden thoroughly after harvest;
- do not plant asparagus in the garden, where before it grew: alfalfa, clover, potatoes, sugar beets.
In the fight against diseases of a fungal origin, drugs can help:
- Fitosporin;
- Topsin-M;
- "Topaz"
- Bordeaux mixture;
- copper oxychloride.
Processing is carried out every 10-14 days, diluting the funds strictly in accordance with the instructions.
Pests
In addition to diseases, pests pose a threat to asparagus and its harvest.
Asparagus leaf beetle
The asparagus leaf beetle is a 5 mm beetle with three pairs of legs. The color of the insect is bright: the general color is deep blue, there is a red border on the back, and the elytra have a yellow ornament.
Females lay eggs on the surface of asparagus leaves and stalks, and to pupate, the larvae descend into the root soil. After 2 weeks, the young generation of the asparagus leaf beetle appears.
These pests prefer to use the leaves and stems of adult asparagus as food, and then they do not refuse young shoots. Thus, insects cause irreparable harm to the crop crop, destroying plantings.
Control measures against the asparagus leaf beetle involve spraying with Karbofos after cutting off the shoots for use in food. Deep digging of soil is recommended to destroy insect pupae.
Asparagus fly
A dark insect up to 8 mm long. A zigzag pattern is clearly visible on the spread wings. The female has a long ovipositor. The asparagus fly is active from late March to early summer.
During the day, in warm weather, asparagus flies are active and mate. On cloudy, cool, rainy days, as well as in the morning and evening, insects sit quietly on the tops of asparagus or weeds around it. Do not fly in unfavorable conditions for them.
An adult female lays up to 15 eggs on asparagus shoots that have just emerged from the ground. On days 4-5, the larvae rush deep into the young rod, feeding on its juices and pulp. While pupating, the young generation of the asparagus fly deforms the stems. Typically, the asparagus will eventually die.
The older the asparagus plants, the more serious the danger is the attack of these insects. In the affected areas, the culture practically remains without leaves, which leads to a lack of nutrition. As a result, the number of new shoots decreases, and the yield decreases annually.
If the shoots appear when the asparagus fly finishes its activity, then they are safe from insect attacks.
It is advisable to introduce actions against this pest in the second year:
- They boil down to the removal of all young shoots before the insects fly out. This leads to the impossibility of laying eggs and the development of young animals. During the period of activity of the asparagus fly, it is necessary to cut off curved, unsuitable shoots in combination with healthy ones.
- In autumn, all asparagus stalks must be removed to avoid the development of asparagus fly pupae. Digging up the area and replanting the asparagus is recommended.
- As chemicals, it is allowed to use those that are absorbed by the surface of asparagus leaves. This will kill not only the adult insects on the outside, but also the larvae inside the plant. Spraying should be carried out every 5 days throughout the entire flight period of insects.
These chemicals include: “Vofatox Sp. 50 EC "," Methylparathion WP "," Foltion 50 EC "," Metathion 50 "and others. Preparation of the solution and its use must be carried out strictly according to the instructions for the preparation.
Shield
The scale insect is a small insect up to 5 mm in length with a removable shell. Laying eggs, females cover them with their bodies until the larvae appear. The offspring attach themselves to the asparagus and remain stationary until their carapace is formed. The lifespan of females is up to 4 months, of males - 4 days.
Both adult scale insects and their offspring are harmful to the culture. Insects feed on plant sap, which is why the asparagus gradually heals and dries up.
Pests do not tolerate treatment with soapy water with salt, alcohol-containing agents. It is possible to use special chemicals in accordance with the instructions, for example, Karbofos. One-time processing of asparagus until the complete destruction of pests is difficult due to the structure of the plants. Therefore, repeat spraying after 10-14 days.
Greenhouse thrips
Greenhouse thrips is a dark-bodied aphid with yellow-green front wings. The size of insects is up to 2 mm. It takes about a month from the period of laying eggs to the formation of an adult. The greatest damage is caused by the larvae of thrips.
The pests suck the juice out of the asparagus. From this, the culture acquires a pale shade, weakens and deforms. Suspended growth reduces the yield of asparagus.
Control measures for greenhouse thrips involve daily irrigation of plantations and treatment of plants with Karbofos.
Numerous diseases and pest attacks threaten asparagus. Knowing how to identify ailments and measures to combat them, it is possible to protect the culture and save the harvest. The main assistants of the gardener are timely agrotechnical measures and preventive work.