Diseases And Pests Of Gladioli (15 Photos): A Description Of Thrips And The Fight Against Them. Why Do Flowers Fade Before They Bloom? Why Do Leaves Turn Yellow And Buds Dry?

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-09 13:15

Gladioli are the favorite flowers of many gardeners. Unfortunately, the attractive appearance of the culture is accompanied by frequent diseases and insect attacks. To preserve plantings in proper form, it is important to understand not only how to treat these plants, but also how to prevent ailments.

Causes and symptoms of defeat

If the leaves of gladioli turn yellow, and the lesion spreads from the top, after which they curl and fall off, then we are talking about drying out. The same disease has symptoms such as the emergence of dark deep spots on the corms and their further decay. This disease occurs due to the use of contaminated planting material or planting on affected areas of the soil. If brown spots appear on the leaves, with an increase in the number of which the plates wither and die off, then we are talking about brown rot.

The same disease is determined by the appearance of the same spots on the stems, flower petals and even peduncles, which over time become covered with a fluffy bloom of an unpleasant gray shade. If the root neck is affected by the disease, then the leaves can die off even without color changes. Again, the use of infected bulbs becomes the cause of the disease of the plant. When the tops of the leaves turn yellow, turn brown and finally dry out, the gladiolus is most likely affected by dry rot . The same can be said about the formation of black and round nodules.

If the peduncles of gladiolus are unnecessarily elongated and bent, but too much time passes before the flowering itself, then we are talking about a flower mosaic. The same is true for the defeat of thrips. By the way, various rots lead to the fact that the buds are painted in a brownish tint, dry, but do not bloom.

If, during flowering, the buds, without having time to bloom, are covered with a slimy substance, and the perianth is "filled" with watery spots, then gladiolus suffers from botrythiasis.

Frequent illnesses

Diseases of gladioli are typical for most bulbous. A detailed description of each of them allows you not only to identify the causes of the disease, but also to understand how you can correct the situation. Very often gladioli suffer from drying out or yellowness, affecting not only the roots, but also the tubers of flowers . In this case, the disease can be either the wilting of the surface plant, or the decay of the corms. If gladioli got sick with yellowness, then all damaged plants and all spoiled corms will have to be destroyed. It is allowed to plant a culture in the same place only after 3-4 years.

Before planting in open ground, the planting material can be kept in the infusion of marigolds for about 8-10 hours. Further, after discarding the peduncles, the shrubs should be watered with the same product. In principle, you can try and dig holes from diseased specimens, reaching the corms, and pour in an infusion of garlic, 30 grams of which is diluted in a liter of water. Next, the holes are sealed with soil mixture, and 5 days later, everything is processed with diluted mustard powder.

Brown rot affects all parts of the plant . To combat it, you must use the rule of crop rotation, be sure to dry the bulbs and store them at the correct temperatures and humidity.

Before planting, the corms are kept in a solution of ordinary baking soda. Infected plants are also sprayed with copper sulfate or Bordeaux mixture mixed with lime.

Rust appears on the roots of flowers, so it is not always possible to detect it immediately. Over time, leaf blades are also affected. Affected tubers will have to be dug up and burned immediately. Other common crop diseases include dry and hard rot, bacterial cancer and gladiolus mosaic. Smut stands apart - this disease affects only those gladioli that are grown in the south, with an abundance of dry hot days.

It is quite simple to define the problem - unusual volumetric, as if swollen, black stripes are formed on the shoots of the culture . It is in these neoplasms that the spores of the fungus settle. Having matured, they leave their "shelter" and are carried by the wind over rather long distances. Thus, even one shrub is capable of infecting the inhabitants of the entire garden plot. Gladioli infected with smut are immediately dug up and burned. Disease prevention is similar to many others - the bulbs are heat treated, and the plantings themselves are sprayed with Bordeaux liquid.

Common parasites

The most common pests found in gladiolus beds are thrips and onion root mites.

Thrips

Thrips harms not only all varieties of gladioli, but also irises, daffodils, carnations and other popular crops. The insect is easy to identify by its appearance: a brown body, from one to one and a half millimeters long, is crowned with a black head . The wings of the pest are fringed. Thrips larvae are light yellow in color and have reddish eyes. Its length is also 1 millimeter.

Adult thrips survive the winter, hiding under the scales of the bulbs. If the temperature is above 10 degrees Celsius, then insects begin to reproduce. Larvae develop right in the bulbs, drawing juices from gladioli. After planting, the reproduction process only intensifies, and the leaf plates of the flowers are covered with spots, whitish and black dots, as well as yellow strokes. When the gladiolus has buds, the thrips get inside.

Due to their effect, flowers begin to fade, dry out and lose their decorative appearance . In autumn, insects move to the lower levels of plantings, choosing a warmer place. During harvesting of corms, thrips crawl under their scales, and the cycle repeats. By the way, it is possible to determine that the planting material is already affected by pests by its appearance.

Since insects feed on juices, the tissue of the bulb begins to shrink and become covered with a brown crust. Further, the onions brighten, become sticky to the touch, and at the end they shrink and turn black.

Root onion mite

The root onion mite becomes a threat to numerous bulbous plants, from the daffodil to the gladiolus itself. Insects grow up to 1, 1 millimeter in length and have a light yellow glossy color. Pests live on the remains of plants in the soil, so they immediately "jump" to the newly appeared plantings . They enter the bulbs through damage or the bottom, after which they begin to lay eggs inside. After a week, the tuber is filled with larvae, which feed on its juice. As you might guess, the development of the gladiolus itself in this case slows down, the surface of the leaf turns yellow and further fades.

Not less often the root onion mite also begins to act on the seed harvested for storage … The presence of old scales and roots only enhances this process. The pest can be detected by the condition of the bulb - it becomes covered with red-brown dust, after which it begins to rot. If such a tuber is planted in the ground, then the entire area will be infected along with the plants growing on it.

Treatment methods

To get rid of thrips, it is necessary to do a number of procedures, combining them depending on the severity of the lesion. With a large population of insects, it is necessary to cut the plants in autumn as early as possible in order to prevent them from sheltering in the lower tiers, and then in the bulbs . Pest control includes such mandatory procedures as the destruction of tops and other plant debris after the end of the season, as well as digging the soil. Infected tubers will need to be processed, either by dipping them into water at a temperature of about 50 degrees for 5 minutes, or by spraying with "Karbofos", 2 grams of which are dissolved in a liter of water. Drying must be followed by processing.

When the corms are stored, if thrips are found, it is necessary to sprinkle them with chalk or special lime . Typically, 20-30 grams per kilogram of planting material. You can also hide the bulbs for 1, 5 months in a bag filled with naphthalene, and 10-15 copies will require only 3-5 grams of powder. Further, the tubers are ventilated and stored without naphthalene.

All contaminated specimens should be destroyed immediately prior to planting. If symptoms of damage appear already on growing gladioli, then they can be cured with 10% "Karbofos", 75 grams of which are diluted in 10 liters of water.

In order not to treat gladioli for ticks, it is important to destroy all plant debris, as well as already infected bulbs, every autumn. The planting material should be freed from roots and old scales, and also sprinkled with gray or chalk, using about 20 grams per kilogram of tubers. In winter, a temperature of 2 to 5 degrees should be adhered to, as well as humidity not exceeding 60%.

Infected onions are kept in water heated to 50 degrees Celsius for about 5 minutes, or they are kept in water heated to 35-40 degrees for a week . In addition, a half-hour or hour-long stay in "Keltan", 3 grams of which is dissolved in a liter of water, or in 30% "Karbofos", 5 grams of which are diluted in a liter of liquid, will be useful.

During the growing season, spraying with "Karbofos" or watering with "Keltan" can help.

Preventive measures

There are a number of measures that can help both prevent disease and repel insects. To begin with, it is important to observe the rule of crop rotation and plant gladioli in a new place every year. Thus, spores and larvae remaining in the soil and in plant fragments will not be able to infect gladioli again … The plantings should receive high-quality ventilation and not be too thickened. Infected plants must be quickly separated from healthy plants, or immediately treated with fungicides.

It is better to use either pine needles or sphagnum moss as mulch . Regular insecticide treatments are also important. To avoid the effects of thrips, you can plant onions, calendula or garlic next to gladioli.