Mango Spiraling Whitefly

The spiraling whitefly, known as Aleurodicus dispersus, is a member of the Aleyrodidae family and is thought to have originated in the humid tropical regions of Central and South America.

Aleurodicus dispersus is considered polyphagous, meaning it can feed on various plant species instead of being dependent on a single host.

This particular whitefly is a significant agricultural pest, particularly in mango farming.

DESCRIPTION

Eggs

These whiteflies are small in size and have an elliptical shape with smooth surfaces. They range in color from yellow to tan and possess numerous small waxy secretions. They are usually found on the underside of leaves, arranged in irregular lines that create a spiral-like pattern, which gives this whitefly its common name.

Larvae

There are four developmental stages in the life cycle of these whiteflies, with the first three stages referred to as larvae, and they continuously feed during this period. The initial larval stage, commonly called a “crawler,” is the only immature stage that possesses functional legs and distinct antennae. Consequently, it is the only stage capable of active movement, while all other immature stages remain stationary.

Once the crawlers settle, they develop a distinctive row of waxy tufts on the front part of their body. These waxy tufts continue to grow as more wax material is secreted. During the third larval stage, glass-like rods of wax begin to appear along the sides of the body. These glass-like rods are expelled through specialized pores on the insect’s body and can reach lengths of up to 8 mm, although most are shorter due to fragmentation.

Pupae

The fourth and final immature stage of this species is known as the pupa. In earlier phases, this stage engages in feeding activities but eventually ceases feeding and undergoes internal tissue reorganization before undergoing molting into adulthood. The pupal stage plays a crucial role in taxonomic characterizations, and its specific characteristics must be observed under a microscope.

Mature pupae of this species possess a significant amount of white cottony secretion that extends upward and outward from the posterior region. This secretion consists of both fluffy and waxy components, forming ribbons that can be as long as or even longer than the body’s width.

Pupae are typically colorless or yellowish, nearly oval in shape, flat, and approximately 1 mm in length and 0.75 mm in width.

Adults

The appearance of these whiteflies bears resemblance to many other species of whiteflies. They are small, measuring approximately 2-3 mm in length, and have a white coloration. Their bodies are covered with a delicate, dust-like waxy secretion. They somewhat resemble miniature moths, and both males and females have wings. The eyes of this whitefly are dark reddish-brown, and the wings are initially transparent upon emerging from the pupal casing. However, within a few hours, they develop a white powdery coating. Notably, the forewings of these whiteflies exhibit two distinctive black spots.

LIFE CYCLE

The female whitefly lays her eggs on the underside of leaves, and each egg hatches into a small and active crawler, similar in size to the egg itself. The crawler moves across the host plant’s foliage and then enters an inactive and sedentary nymph stage, attaching itself to the underside of the leaves. During this stage, the nymph extracts nutrients from the leaves.

The nymph stage lacks visible legs and undergoes growth through several molting stages called instars. With each instar, the nymph produces increasing amounts of wax and sugar secretions. The final instar serves as the pupal stage, from which the adult whitefly emerges.

The duration from egg to adult can be less than three weeks in warmer conditions, but it may take longer in cooler conditions. The female whitefly, which appears identical to the male, can lay a substantial number of eggs depending on the prevailing temperature.

Females begin laying eggs within a day of emerging and continue to do so throughout their lifespan. Unmated females produce exclusively male offspring, while mated females produce both males and females.

Only the adult stage has the ability to move beyond the leaf where the egg was laid.

DAMAGE

Mango spiraling whiteflies are typically active during calm and still periods of the day, such as dawn and dusk. They inflict both direct feeding damage and indirect damage.

Direct damage occurs when the immature and adult stages of whiteflies pierce the foliage and extract sap through their feeding. The most significant damage is caused by the first three nymphal stages. This feeding activity often leads to the premature dropping of leaves.

Indirect damage arises from the accumulation of honeydew and the white, waxy flocculent material produced by the whiteflies. This sweet and watery excretion becomes a food source for bees, wasps, ants, and other insects.

The honeydew also acts as a substrate for the growth of sooty mold. This mold results in the darkening of leaves, reduces photosynthesis activity, diminishes plant vigor, and frequently distorts the appearance of the plant. Ultimately, it lowers the market value of the fruits, rendering them unmarketable. Additionally, the wind disperses the flocculent material produced by the nymphs, creating an unsightly nuisance.

MANAGEMENT

Chemical method

Chemical intervention has proven to be the most effective approach in managing this pest.

For effective control, it is recommended to use insecticides that possess both contact and systemic properties. The following products are suggested for this purpose:

  • TAURUS 500SP: Mix 10 grams with 20 liters of water.
  • PROFILE 440EC: Mix 30 milliliters with 20 liters of water.
  • PRESENTO 200SP: Mix 5 grams with 20 liters of water.
  • EPITOME ELITE 500SP: Mix 10 grams with 20 liters of water.
  • LEXUS 247SC: Mix 8 milliliters with 20 liters of water.
  • EMERALD GOLD 700WDG: Mix 5 grams with 20 liters of water.
  • AMAZING TOP 100WDG: Mix 5 grams with 20 liters of water.
  • EMERALD 200SL: Mix 10 milliliters with 20 liters of water.
  • LOYALTY 700WDG: Mix 5 grams with 20 liters of water.
  • DEFENDER 25EW: Mix 40 milliliters with 20 liters of water.

By using these insecticides according to the recommended dosages and dilutions, effective control measures can be implemented for managing the pest.

Non-chemical control methods

  • Opt for plant varieties that exhibit resistance to the pest.
  • Utilize sticky traps as a means of control.
  • Maintain good field hygiene and sanitation practices.
  • Ensure proper weed control within the field.
  • Implement crop rotations with non-host plants.
  • Prune excessive branches to create an “umbrella” appearance for the plant, allowing for scattered openings in the canopy. This permits sunlight, wind, and rain to penetrate, reducing the foliage surface area requiring treatment and eliminating shelter for the spiraling whitefly.
  • Provide adequate nutrition to enhance plant vigor, as healthy plants are more resilient to spiraling whitefly infestations.

Note:

  • Enhance the effectiveness of insecticides by mixing them with INTEGRA at a rate of 3 milliliters per 20 liters. INTEGRA serves as a sticker, spreader, penetrant, and wetter.
  • To prevent the development of resistance to any specific insecticide, it is highly recommended to alternate the use of multiple insecticides throughout the crop’s season, rather than relying on a single chemical.
  • For cleaning sooty mold, apply JAMBO CLEAN at a rate of 100 milliliters per 20 liters, and spray it onto the crop.
  • Timely management of the pest is crucial for effective control.

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