Whitefly: photo and description of a dangerous greenhouse pest

A small whitefly, the photo of which can be viewed just below, is one of the most dangerous enemies of plants growing in closed ground. Most often, this pest appears in greenhouses and greenhouses with insufficient ventilation. Today we consider the two most common types of whiteflies, especially their development and causes.

Greenhouse Pests

The birthplace of cotton or tobacco whiteflies is presumably India. This type of pest is widespread, it is especially common in places with high humidity and high air temperature. Parasitizes on vegetable, technical, decorative and gourds.
The greenhouse or greenhouse whitefly also prefers a warm and moist environment, is widespread in closed ground, where it affects both ornamental and vegetable crops. For the normal development and activity of whiteflies, an air temperature of about +25 ... + 35 ° C and increased humidity are required. Under such conditions, approximately 15 generations of the parasite successfully develop in one year alone.

Description

Whitefly looks like a small moth. The body length of males reaches 0.9 mm, the females are somewhat larger. The body of an adult is painted yellow. The wings have a uniform white color, without any spots and splashes. There are light yellow antennae on the head.

Despite the fact that these pests are insects with an incomplete transformation cycle, their development is rather complicated. In addition, whiteflies can exist and reproduce only in warm and humid climates, so it can be assumed that it hibernates where its optimal conditions remain - in a greenhouse or in a greenhouse.

Eggs

Throughout life, the duration of which is no more than 30 days, one female is able to lay from 85 to 130 eggs. They make masonry at a temperature of about + 25 ° C and eggs are laid out, usually in the form of a ring.

On a note! An embryo developing in an egg does not tolerate low air temperatures and dies almost immediately when cold weather sets in!

The female greenhouse whitefly lays eggs mainly on young leaves and shoots, both crowded and scattered. Each egg has a tiny stalk. Initially, it is painted yellow. After nine days, the egg turns black and slightly increases in size - up to about 0.25 mm.

On a note! Females predominate in whitefly populations, more than twice as many as males. And the reason for the birth of daughters is mainly symbiotic bacteria belonging to the Rickettsia group!

Larvae

Whitefly larva has 4 stages of development.

1. At the first stage, it is wingless and mobile. The length of the flat oval body of the young larva does not exceed 0.3 mm; it has clearly distinguishable antennae and legs. During the first 15 hours of its life, the larva is in search of a source of food, and as soon as it finds a suitable leaf or shoot, it immediately tightens its legs under itself and sticks to it.In the process of feeding, the wax glands of the larva secrete a special secret, which spreads around it with a dense barrier and attaches to the surface of the leaf or shoot. Then the larva molts, after which its antennae and legs become noticeably smaller, and as a result, it loses mobility. The duration of this phase is 10-14 days.
2. In the second stage, the larva resembles a small shiny flake. She has rudimentary antennae and legs.
   
3. The third stage is the nymph. At this time, the body of the larva is covered with a waxy coating and acquires a greenish tint. On the front of the body, red eyes can be distinguished.
4. Up to the fourth stage, the larvae of the greenhouse whiteflies openly live on the underside of the leaf. At the final stage, her body grows to 0.75 mm and at the same time it swells and its shape noticeably changes.

During this period, the larva no longer feeds and undergoes reorganization - the beginnings of the wings appear, the length of the legs increases, the antennae and other organs that adults have grow. This stage lasts about 12-15 days.

Then adults appear who live no more than 14 days. Young whiteflies flying out of the puparium already have fully formed wings.

On a note! The development of whiteflies from eggs to adults may depend on the host plant. For example, on cucumbers this path takes about 18 days, on tomatoes, carrots and flax - no more than 30 days!

Features of development and life

In the closed ground, the development of whiteflies occurs throughout the year, in the open ground their constant activity is maintained exclusively in the southern regions. Inhabited in warm, moist shelters, this pest is able to multiply and develop very quickly.

In temperate latitudes, provided sufficient moisture and appropriate air temperature, the flight of these insects can be observed even in the wild. However, since such conditions are short-lived in these regions, the whitefly overwinters exclusively in the greenhouse or in the greenhouse. For wintering, females choose the most secluded corners of the room, sometimes they can sink shallow into the soil. Heaps of compost and uncleaned plant debris are also attractive to them.

Whitefly poses a huge threat to more than 600 species of various plants and is especially dangerous when it appears in greenhouses and greenhouses. In addition to the above cultures, its owners often become:

• flower plants;
• valuable medicinal herbs;
• fruit trees;
• berry bushes;
• citrus;
• forest tree plantations.

Whitefly, at whatever age and phase of development, is in need of amino acids, and therefore feeds exclusively on plant juices. As a result, the insect quickly deprives him of vitality, which leads to imminent death. In addition, in the process of life, larvae secrete processed products that contain a large amount of sugars. The latter, in turn, are an excellent environment for the development of various fungi. Thus, whitefly strikes plant health in two directions at once.

Causes of infection

The main reason for the appearance of whiteflies is increased humidity and high air temperature. In addition, the pest is most often planted in those greenhouses and greenhouses in which plants are planted very often, due to which normal air circulation is disturbed.

But the reasons may be different:

• entering untreated plants into the greenhouse for wintering from the street;
• purchase in the store of infected seedlings;
• relocation of seedlings from an infected greenhouse;
• purchase or entry from a site of contaminated soil.

On a note! Whitefly can get into the greenhouse along with the seedlings that you grew in the apartment. Moreover, before penetrating into a warm, moist shelter, the insect could well have been undetected, since it was in hibernation!

Knowing these reasons, it is quite easy to prevent the intruder from entering the greenhouses.First of all, it is desirable to treat the erected greenhouse with pesticides and equip it with a sufficient number of window leaves and doors to ensure normal ventilation. Growing vegetables and other crops, always follow the rules of agricultural technology: try to maintain the required temperature of air and soil, periodically ventilate the room, prevent thickening of plantings and monitor humidity. These simple preventive measures will help prevent the reproduction of not only whiteflies, but also other greenhouse pests.