Tomato Thrips

Tomato thrips, an insect pest that inflicts significant economic losses on tomato crops, is known for its ability to directly and indirectly harm the plants. With their piercing-sucking mouthparts, they feed on the mesophyll and epidermal cells of plant tissues.

The presence of thrips can lead to damage to tomato harvests, particularly in the early stages when seedlings are vulnerable. This is because thrips thrive on expanding plant tissues, which can result in the destruction of young plants before they have a chance to become robust.

These pests flourish in hot and dry conditions, making them particularly damaging in regions where such climatic conditions persist throughout most of the production season.

Tomato thrips are highly adaptable and have a wide range of food sources. In addition to tomato crops, they also feed on various field crops, vegetables, flowers of different types, bedding plants, and weedy plants.

IDENTIFICATION

Eggs:

The eggs of this species are tiny, opaque, and kidney-shaped. They are usually laid individually in a scattered arrangement, although sometimes they may be found in rows alongside or beneath veins. The female makes an incision in the parenchyma tissue of leaves, flowers, or fruit using her saw-like ovipositor and partially or completely inserts the eggs into these incisions.

Eggs are prone to drying out.

Larvae:

Both larvae and adults are the only stages of this species that feed.

Pupae:

Between the larval and adult stages, there are two non-feeding stages, both of which have functional legs. The first stage is…

Adults:

The adults of this species have a slim, dorso-ventrally flattened body shape, and their four wings are adorned with long hairs along the edges. When at rest, the wings are folded lengthwise over their back.

Females come in three different color variations (pale, intermediate, and dark), and all three forms can mate with pale-colored males.

Mature adults measure approximately 1.5 mm in length and display a pale yellow to light brown coloration.

Adults are the only life stage capable of flying, although their flight ability is not particularly strong. They can be transported by wind currents, cling to clothing, or be found in association with plants.

LIFE CYCLE

Adult thrips emerge from eggs and progress through two active feeding larval phases and two non-feeding phases, known as prepupa and pupa, before reaching adulthood.

During the later stages of larval development, thrips undergo significant changes in their appearance and behavior and are referred to as prepupae and pupae, despite the absence of a true pupal stage.

Female thrips deposit their elongated, cylindrical, or kidney-shaped eggs on leaves, buds, or other parts of plants. The pale prepupae and pupae of most species either fall to the ground, settle in leaf litter, find shelter within plant crevices, or inhabit galls.

The duration of the thrips life cycle, starting from egg to adult, varies depending on the environmental conditions. Typically, it ranges from 30 to 45 days, but can be as short as 14 days, particularly in warm weather.

Thrips undergo multiple generations within a single year.

FEEDING & DAMAGE

Thrips exert direct harm by consuming fruits, flowers, leaves, and shoots, significantly impacting the visual appeal of crops.

Plants that are affected display inhibited growth, and their damaged leaves exhibit a papery texture, distortion, the formation of minute pale spots (referred to as stippling), and premature shedding.

Both flowers and leaves take on a distinct “silvery” appearance, and an extensive infestation can lead to the abortion of flowers.

Infested terminals may undergo discoloration and rolling.

The feeding area may contain small black fecal deposits, resembling little black spots.

Additionally, female thrips can cause damage to plant leaves when they insert their eggs into the plant tissue using their sharp ovipositor.

Moreover, thrips serve as vectors for the Tomato spotted wilt virus, which can rapidly devastate entire tomato plantations.

MANAGEMENT

Chemical method

To effectively manage the thrips pest and prevent the in-field spread of Tomato spotted wilt virus, it is recommended to employ foliar insecticide sprays early in the season and continue treatment as necessary throughout the season.

In order to minimize the development of insecticide resistance in thrips, it is advisable to rotate the use of different classes of insecticides.

For the successful control of tomato thrips, the following insecticides are recommended:

  • ALONZE 50EC: Mix 5ml with 20 liters of water.
  • PROFILE 440EC: Mix 30ml with 20 liters of water.
  • DEFENDER 25EC: Mix 40ml with 20 liters of water.
  • AMAZING TOP 100WDG: Mix 5g with 20 liters of water.
  • LEXUS 247SC: Mix 8ml with 20 liters of water.
  • EPITOME ELITE 500SP: Mix 10g with 20 liters of water.
  • SINOPHATE 750SP: Mix 20g with 20 liters of water.
  • PRESENTO 200SP: Mix 5g with 20 liters of water.
  • OCCASION STAR 200SC: Mix 5ml with 20 liters of water.

Please ensure to follow the recommended dosages and dilution ratios for effective control of tomato thrips.

Non-chemical methods

To mitigate thrips infestations, it is recommended to implement the following measures:

  1. Avoid planting tomatoes in close proximity to onions, garlic, or cereals, as these crops tend to attract high numbers of thrips.
  2. Steer clear of fields that are located near greenhouses where ornamental plants such as cut flowers are cultivated. These plants can act as hosts for both the virus and thrips.
  3. Encourage the presence of natural enemies of thrips, such as predatory insects, to help control their population.
  4. Implement crop rotations with non-host plants to disrupt thrips life cycles and reduce their overall numbers.
  5. Opt for tomato varieties that possess resistance or tolerance to thrips, as these can withstand infestations better.
  6. Maintain proper weed control in and around tomato fields, as weeds can serve as alternate hosts for thrips.

Important note: When applying insecticides, it is recommended to mix them with INTEGRA at a ratio of 3ml per 20 liters of water. INTEGRA acts as a sticker, spreader, and penetrant, enhancing the effectiveness of the chemical treatment.

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