How To Get Rid Of Gladiolus Thrips

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Gladiolus biology

To more clearly represent this pest on the gladiolus and more clearly calculate the measures to combat it, you need to briefly describe the biology of the plant itself. Gladiolus is a perennial herb that has a corm in the lower part of the stem with several dormant buds, of which, as a rule, only one develops.

It has a straight stem with a few xiphoid leaves (up to 90 cm long). The inflorescence (ear) consists of 6-20 large flowers, which are located on the peduncle in 1-2 rows. In some varieties, the ear can be up to 1.5 m long and have up to 28 buds. Flowers alternately open from bottom to top (3-12 flowers sometimes bloom at the same time). Gladiolus blooms from July to September.

Its early varieties bloom 70 days after planting, mid-early ones - after 80 days, late - after 90 days. The corms of gladioli are round, with a diameter of 2 to 8 cm, depending on the variety and age. Every year, the old corm is depleted and dies off by autumn; instead of it, a new one is formed, children appear (0.1-1 cm in size).

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Of the numerous pests of gladiolus, gladiolus thrips, a small (1-1.5 mm long) insect (dark brown in color), causes a lot of trouble for the grower. This winged pest (its light, fringed wings are folded on the back) is able to move even in one flight over rather considerable distances, therefore, during the summer period it can master a very large territory.

Thrips and its larvae (yellow-brown color) suck the plant sap from the leaves, which, as a result of such damage, become grayish, dry, rough (whitish streaks and black dots are clearly visible on them at the bite sites). Flowers inhabited by the pest are deformed (the edges of the perianth lobes become thinner), look withering, discolored.

With severe damage, the buds (especially the upper ones) do not open, they look like glued together, dry out, and the peduncle itself bends. In this case, it is easy to detect yellow larvae and young thrips if you look into the leaf axils or unfold the bud wrappers. At the end of the growing season of early varieties, the pest moves to feed on medium-early varieties, then to late varieties, therefore, it gives several generations per season.

To begin a favorable development, thrips needs a temperature of at least 10 ° C. The female lays up to 25 eggs in gladiolus tissue, from which initially white larvae hatch within 12-15 days (depending on weather conditions). The pest reproduces most actively in dry, hot weather. With a strong decrease in temperature (for example, when freezing to -3 ° C), it dies.

With a cold weather to 8 ° C, it goes into the soil (but does not hibernate there), but climbs under the scales of corms, with which it endures an unfavorable winter period in storage conditions. Since the harvesting of young bulbs (especially mid-early varieties) is carried out quite early (usually before the onset of severe cold weather), the thrips enters the storage along with the harvest, where it continues to actively feed and multiply for some time (and at a sufficiently high storage temperature, even in winter), sucking juices already from corms.

As a result of numerous bites, the surface of the plant material takes on a dull appearance, speckled with small dots, and becomes rough to the touch. With a high number of insects and a large amount of damage on the corm, the formation of brownish crusted spots is observed. Due to such a strong effect of the pest, the corm and its sprout dry out greatly, and when bulkhead and cleaning, yellow dust spills out from such plant material, irritating the nasal mucosa of the grower and capable of causing allergies.

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Control measures for gladiolus thrips

After purchase, the seed is treated before planting for prophylaxis, for example, with a solution of fufanon, ke (10 ml / 10 l of water) or actellik, ke (20 ml / 10 l). During the growing season, the health of the plants is closely and weekly monitored.

At the first appearance of a pest on a plant, this often happens in mid-June, the foliage is sprayed using both vegetable extracts of garlic, tobacco, makhorka, and the above insecticides. Fitoverm, ke (8 ml / l of water) can be recommended as a biological preparation. Plant treatments are carried out at intervals of 10-14 days; during the flowering period, the concentration is reduced by a third.

Experts recommend alternating insecticides in order to prevent the pest from getting used to a certain drug. When the temperature drops below 9 … 10oС, the pest goes into the soil, so there is no point in spraying during such periods. If by the fall it was not possible to destroy the pest, then after harvesting the corms are soaked in solutions of the drugs recommended above. For example, after digging the corms, they are treated with a 0.1% solution of fufanon for 10-15 minutes, and in the spring this operation is repeated.

For the destruction of thrips, some growers resort to spring pre-planting heat treatment of corms with hot water (at a water temperature of 42 … 44 ° C for 1 hour or at 50 ° C - 10 minutes). This procedure must be approached with extreme caution, strictly maintaining the temperature regime so as not to "cook" the seed. Other amateurs, for prophylactic purposes, carry out pre-planting soaking of corms in diluted garlic juice for 1 hour.