Cotton Whitefly Control: How to Select Insecticides Based on Different Life Stages

The cotton whitefly (Cotton Whitefly) is one of the sucking pests that requires priority management in cotton production. Under warm climatic conditions, whiteflies can reproduce rapidly and form continuously growing populations on the undersides of leaves.

Not only do they affect cotton plant growth by sucking plant sap, but they also secrete large amounts of honeydew. When honeydew adheres to open cotton bolls and cotton fibers, it can cause “sticky cotton,” which affects harvesting, ginning, and subsequent spinning processes.

Одна з часто недооцінених проблем у боротьбі з бавовняною білокрилкою полягає в тому, що яйця, німфи та дорослі особини мають різні біологічні характеристики, і не всі інсектициди можуть контролювати ці стадії життя однаково.

For example, buprofezin primarily targets the molting process of nymphs, while pyriproxyfen mainly disrupts normal insect development and the formation of adults. Acetamiprid, on the other hand, is an insecticide with a nervous system mode of action and can be used to manage active populations covered by the label.

Якщо вибір продукту базується виключно на назві інсектициду або ринковій ціні без урахування стадії життя шкідника, популяції дорослих особин можуть тимчасово скоротитися, але німфи на нижньому боці листя продовжуватимуть розвиватися.

Therefore, effective cotton whitefly management requires integrating the pest life cycle, cotton growth stages, field monitoring, and the IRAC mechanism of action.

For pesticide importers, distributors, and registration companies, understanding the technical positioning of different active ingredients also helps in establishing a more rational portfolio of cotton insecticide products. For comprehensive cotton pest, disease, and weed management, please refer to POMAIS’s Cotton Crop Protection Solutions.

What is the cotton whitefly? Why does it require focused management?

One of the major economically significant whiteflies on cotton is the tobacco whitefly (бемізія табаці). It belongs to the family Aleyrodidae within the order Hemiptera and constitutes a complex population comprising multiple cryptic species, distributed across tropical, subtropical, and some temperate agricultural regions.

It is important to note that not all small, white flying insects in cotton fields are the same species of whitefly. Different whitefly species may vary in appearance, host range, and economic impact; therefore, the target pest should be identified before developing a control strategy.

What are the major populations of Bemisia tabaci?

From an agricultural control perspective, MEAM1 and MED are the two lineages of the tobacco whitefly complex that receive the most attention.

систематика	Англійська назва	Historically Used Names	Міркування щодо управління
MEAM1	Middle East-Asia Minor 1	Biotype B	Widespread distribution with strong host adaptability
MED	Середземне море	Biotype Q	Some populations pose a high risk of insecticide resistance

In the past, agricultural literature often used “Biotype B” and “Biotype Q” to describe these two population types. It is now recommended to use taxonomic names such as MEAM1 and MED.

Population composition and resistance patterns vary by region. Particularly in cotton-producing areas where insecticides have been used for a long time, one cannot determine a pest’s sensitivity to a specific active ingredient based solely on its appearance.

What damage do whiteflies cause to cotton?

Both adult and nymph whiteflies obtain nutrients by piercing and sucking sap from the phloem of plants. When population densities are high, sustained feeding can impair the normal growth of cotton plants.

Major damages include:

Тип пошкодження	Специфічні симптоми	Impact on Cotton Production
Пряме годування	Leaf chlorosis, yellowing, and curling	Impairs normal photosynthesis
Stunted plant growth	Decreased vigor; leaf drop in severe cases	May affect boll formation and yield
Honeydew secretion	Sticky substance appears on the surface of leaves and cotton bolls	Increases the risk of cotton fiber contamination
Сажистий цвіль	Black sooty mold fungi grow on the surface of honeydew	Reduces the visual quality of leaves and fibers
Передача вірусу	Some whitefly populations transmit the Cotton leaf curl virus	May cause additional losses in regions where the virus is present
Post-Harvest Processing Issues	Honeydew adheres to open cotton bolls and fibers	Affects picking, ginning, and spinning processes

Among these, “Sticky Cotton” is a particular concern in commercial cotton production.

Once the cotton bolls open, the honeydew comes into direct contact with the cotton fibers, which can make the fibers sticky, increase the difficulty of cleaning ginning equipment, and affect the quality of yarn processing.

Therefore, thrips management affects not only field yield but also the commercial value of the final cotton product.

How Does the Life Cycle of the Cotton Whitefly Affect Pesticide Selection?

Before selecting a pesticide, it is essential to understand the life cycle of the whitefly.

The cotton whitefly is an insect with incomplete metamorphosis, primarily undergoing egg, nymph, and adult stages. Nymphs have multiple instars; the first-instar nymphs possess limited mobility, while subsequent instars gradually become sessile, feeding on the surface of leaves.

Стадія яйця

Whiteflies typically lay their eggs on the underside of leaves. The eggs are oval or slightly elongated, and in some species, they have short stalks.

Whiteflies do not feed directly on plants during this stage, but once the eggs hatch, they form a new population of nymphs.

Вибираючи пестицид, враховуйте наступне:

• Чи дорослі особини все ще відкладають яйця.
• Whether there are large numbers of fresh eggs in the field.
• Whether the candidate active ingredient affects egg development or subsequent hatching.
• Whether the product has the appropriate label use.

For example, pyriproxyfen can affect whitefly populations by disrupting insect development and reproductive processes, but it should not be simply viewed as a contact insecticide capable of rapidly killing all eggs.

Crawler Stage—First-instar Nymphs

After whitefly eggs hatch, first-instar nymphs, also known as crawlers, emerge.

This is the mobile stage within the immature life cycle. The nymphs briefly search for a suitable feeding site before settling on the underside of a leaf.

This stage warrants close monitoring because it represents the establishment of a new generation of whiteflies.

Ключові спостереження включають:

• Кількість щойно вилупилися німф.
• The distribution of nymphs on the underside of leaves.
• Whether large numbers of adults are continuously migrating in and laying eggs.
• The activity of natural enemies and parasitic wasps.

Once first-instar nymphs have established a population, they will subsequently enter the stationary feeding stage; therefore, timely detection of new populations helps determine future control windows.

Nymph Stage—Mid-to-Late Nymphal Stages

Whitefly nymphs undergo multiple developmental stages. After the first instar, nymphs gradually lose their ability to move and remain stationary on the underside of leaves to continue feeding.

Second- through fourth-instar nymphs are key targets for field surveys.

Among these, fourth-instar nymphs typically exhibit distinct red eye spots and are often referred to as the “Red-Eye Stage” or “Puparium.”

It is important to note that whiteflies are insects with incomplete metamorphosis; this stage does not constitute a true pupal stage as defined for insects with complete metamorphosis.

Key management considerations for this stage include:

• The number of nymphs on the underside of leaves.
• The proportion of older-instar nymphs.
• Whether nymphs are still alive.
• Natural mortality due to parasitism and predation.
• Whether it is necessary to use active ingredients effective against immature life stages.

Active ingredients such as buprofezin, pyriproxyfen, and spiromesifen can be considered as options in different nymph management strategies, but their modes of action differ.

Дорослий етап

Adults have two pairs of wings covered with a white powdery substance and are primarily active on the undersides of leaves and near the plant canopy.

When plants are disturbed, adults may quickly fly away from the leaves.

The adult stage is critical for population reproduction and dispersal, as adults continue to lay eggs and establish new populations.

Therefore, adult management should focus on the following considerations:

• Чи продовжує зростати кількість дорослих особин у полі.
• Whether whiteflies have migrated from nearby host crops.
• Whether adults have already begun laying eggs in large numbers.
• Whether adult control measures appropriate for the current pest situation need to be implemented.

Insecticides such as acetamiprid, which are effective against whiteflies, can be considered for managing adults and active populations; specific use should be based on local registrations and product labels.

Майте на увазі: зменшення чисельності дорослих особин не означає, що популяція німф зникла. If only adult numbers are observed without checking for immature stages on the undersides of leaves, the risk of subsequent population growth may be underestimated.

Which insecticides are suitable for different life stages of whiteflies?

Since different active ingredients have different modes of action, selection should first identify the predominant life stage in the field, followed by consideration of the pesticide’s actual control efficacy.

The following active ingredients warrant priority evaluation in cotton whitefly management.

Comparison of Life Stages and Active Ingredients in Insecticides

Major Life Stages of Whiteflies	Candidate Active Ingredients	Група IRAC	Key Mode of Action
Яйця та незрілі стадії	Пірипроксифен	7C	Interferes with insect development and reproductive processes, affecting adult formation
Німфи	Бупрофезин	16	Interferes with chitin biosynthesis and normal molting
Німфи	Спіромесифен	23	Inhibits lipid biosynthesis; primarily targets immature life stages
Immature life stages	спіротетрамат	23	Пригнічує біосинтез ліпідів; проявляє системну активність
Дорослі та активне населення	Ацетаміпрід	4A	Діє на нікотинові ацетилхолінові рецептори комах
Дорослі та активне населення	Флупірадіфурон	4D	Butenolide class; acts on nicotinic acetylcholine receptors
Rapid control of adults	Біфентрін	3A	Клас піретроїдів з нейротоксичним механізмом дії

This table is intended to explain the technical classification of candidate active ingredients; it does not imply that all products have the same control efficacy, nor does it imply that these ingredients are registered for use against cotton whiteflies in all countries.

Pyriproxyfen—primarily targets immature developmental stages

Pyriproxyfen belongs to IRAC Group 7C and is classified as a juvenile hormone analog.

It interferes with the insect’s normal growth, development, and reproductive processes, thereby disrupting the normal transition of whiteflies from immature stages to adulthood.

In whitefly management, its technical applications primarily include:

• Inhibiting normal egg development and hatching.
• Interfering with the development of mature nymphs into adults.
• Вплив на репродуктивну здатність дорослих особин.
• Reducing the ability to establish subsequent populations.

The mode of action of pyriproxyfen means it is not suitable for use as a product designed to rapidly knock down adults.

After application, even if adult populations do not decline immediately, the product’s effectiveness should not be judged based solely on short-term observations. Monitoring of newly hatched nymphs, mature nymphs, and adult emergence must continue.

Additionally, resistance of the cotton whitefly to pyriproxyfen has been detected in some regions; therefore, local resistance data must be consulted to determine whether its use is still appropriate.

Buprofezin—Focus on the Nymphal Molting Process

Buprofezin belongs to IRAC Group 16 and primarily acts by interfering with the biosynthesis of insect chitin and the normal molting process.

It is an active ingredient worthy of special attention in the management of cotton whitefly nymphs.

Його основні характеристики включають:

• Primarily targets the nymphal developmental stage.
• It disrupts normal molting and subsequent development.
• It is not an insecticide that provides rapid knockdown of adults.
• Найкраще оцінювати його разом з опитуваннями німф та тенденціями популяції.

When using buprofezin, attention must be paid to the age and survival status of the nymphs; effectiveness should not be judged solely by whether adults die immediately.

Якщо основною проблемою на місцях є безперервний приплив великої кількості дорослих особин, і на нижньому боці листя ще не сформувалася значна популяція німф, то використання продукту, спрямованого лише на німфи, може не повністю вирішити поточну проблему.

Спіромезифен — інгібітор біосинтезу ліпідів

Спіромезифен належить до групи 23 IRAC та впливає на нормальний розвиток, пригнічуючи процеси, пов'язані з біосинтезом ліпідів комах.

In whitefly management, it is primarily used to control immature life stages.

Factors to consider when selecting a product:

• Whether a significant number of nymphs are present in the field.
• Whether the nymphs are at a developmental stage suitable for control.
• Whether the undersides of leaves can be adequately covered.
• Чи існує опір Групи 23 серед місцевого населення.

Spiromesifen and Buprofezin have different modes of action; therefore, their technical positioning is not the same.

Однак не слід ігнорувати їхні відповідні сфери реєстрації та фактичну ефективність контролю лише тому, що вони належать до різних груп IRAC.

Spirotetramat—A Group 23 Product with Systemic Translocation Properties

Spirotetramat also belongs to IRAC Group 23.

It affects the development and reproduction of sucking pests, such as whiteflies, by inhibiting lipid biosynthesis.

One of its key technical characteristics is its ability to translocate bidirectionally within the plant, which helps distribute the active ingredient to different parts of the plant.

However, although Spirotetramat and Spiromesifen are different active ingredients, they belong to the same IRAC group.

Тому:

• The two should not be considered rotation products with different modes of action.
• Слід звернути увагу на місцеві ситуації опору в межах Групи 23.
• The scope of application must be determined based on the specific product’s application method and label.
• The systemic translocation capability should not be interpreted as providing unconditional control of all whiteflies on the undersides of leaves.

Ацетаміприд — лікування дорослих та активного населення

Ацетаміприд належить до групи 4A IRAC та є неонікотиноїдним інсектицидом.

It acts on the insect nicotinic acetylcholine receptor (nAChR), disrupting normal neural transmission and causing neurological dysfunction in susceptible pests.

In the management of cotton whiteflies, acetamiprid can serve as a candidate active ingredient for managing adults and active populations.

Key considerations when selecting this product include:

• Whether the current adult population is increasing.
• Чи залишається цільова популяція вразливою до групи 4А.
• Чи має продукт відповідну реєстрацію на бавовняних та білокрилок.
• Whether other Group 4A products have already been used.
• Whether there is currently a risk of exposure to bees and other non-target organisms.

POMAIS offers a variety of acetamiprid product formulations, including 20% SP, 15% SP, 20% WP, 25% WP, and other project-specific formulation options.

Ви можете переглянути Acetamiprid insecticide product specifications for details on the active ingredient, CAS number, IRAC group, formulation, and technical documentation.

Please note that product specifications and proposed uses do not imply that the product has already obtained the corresponding registration in the target country. Specific scope of use must be determined by the locally approved label.

Флупірадіфурон — ще один варіант дії

Flupyradifurone belongs to IRAC Group 4D and is classified as a butenolide.

It also acts on the nicotinic acetylcholine receptors of insects but belongs to a different subgroup than the neonicotinoids in Group 4A.

In some whitefly management systems, it can serve as a candidate for controlling active populations.

However, although Group 4A and Group 4D belong to different subgroups, this does not mean that cross-resistance does not exist in all regions. When rotating products, decisions should still be based on local resistance mechanisms and IRAC recommendations.

Bifenthrin—A Broad-Spectrum Insecticide Requiring Careful Evaluation

Bifenthrin belongs to IRAC Group 3A and is classified as a pyrethroid insecticide.

In some cotton production systems, it can be used to control adult whiteflies at specific life stages.

Однак його не рекомендується використовувати як рутинний засіб першої лінії для всіх стадій росту бавовни.

Основні причини включають:

• Whitefly populations in some regions have already developed resistance to pyrethroids.
• Broad-spectrum insecticides may affect parasitic wasps and predatory natural enemies.
• Inappropriate early use may increase the risk of outbreaks of secondary pests such as leaf mites and aphids.
• Control of nymphs cannot simply be equated with rapid control of adults.

Therefore, the decision to use bifenthrin requires a careful consideration of the pest life stage, local resistance, the cotton growth stage, and risks to non-target organisms.

How should whitefly management be planned for different cotton growth stages?

Окрім власного життєвого циклу білокрилки, стадія росту бавовни також впливає на стратегії боротьби.

The same whitefly population may pose different economic risks during the vegetative growth stage compared to the boll-opening stage.

Стадія розсади та стадія раннього вегетативного росту

Під час стадії проростання бавовни особливу увагу слід приділяти міграції білокрилки з навколишніх культур-господарів.

Nearby cucurbits, vegetables, weeds, and other host plants may provide a breeding and survival environment for whiteflies.

When these crops are harvested, or the plants die back, adult whiteflies may migrate into nearby cotton fields.

Фокус управління:

• Check the edges of cotton fields for adult whiteflies.
• Inspect the undersides of leaves for eggs and early-instar nymphs.
• Monitor the harvest and removal of nearby host crops.
• Avoid preventive, broad-spectrum applications without evidence of an infestation.
• Protect parasitic wasps and predatory natural enemies.

If only a small number of migrating adults are found, but a stable nymph population has not yet formed, first determine whether intervention is necessary based on local monitoring standards.

Vegetative Growth and Budding Stages

As the number of leaves on cotton plants increases, whiteflies can establish populations on the undersides of more leaves.

During this stage, special attention should be paid to nymph numbers and their developmental status.

Management Priorities:

• Inspect the undersides of middle and upper leaves.
• Record the numbers of eggs, first-instar nymphs, and mid-to-late-instar nymphs.
• Determine whether there is a sustained increase in mature nymphs.
• Decide whether to use an IGR based on local control thresholds.
• Prioritize evaluating selective pesticides that are relatively friendly to natural enemies.

If a nymph population is establishing, active ingredients such as buprofezin, pyriproxyfen, or spiromesifen can be considered as treatment options, but selection should be based on the target life stage and local product registrations.

Flowering and Boll Formation Stages

As the crop enters the flowering and boll formation stages, the cotton canopy gradually expands, and whitefly populations may continue to grow.

At this time, field surveys should be intensified, particularly when large-scale harvests of surrounding host crops are underway, and climatic conditions favor whitefly reproduction.

Key points to monitor:

• Whether adult populations are continuing to increase.
• Whether nymph populations have established in large numbers during the mid-to-late stages.
• Whether significant honeydew is present in the field.
• Whether natural enemies have been affected by earlier pesticide applications.
• Whether cotton boll formation is proceeding normally.

If both adults and nymphs are present, first determine whether the primary issue stems from the continued influx of adults or from a stable breeding population that has already established itself in the field.

Do not simply assume that a single pesticide can control all life stages.

From Boll Opening to Harvest

Це критично важливий етап контролю якості в боротьбі з бавовняною попелицею.

As the bolls open, the cotton fibers are gradually exposed to the external environment. If the aphid population is high, honeydew may adhere directly to the cotton fibers.

This situation can lead to “Sticky Cotton,” which further affects ginning, spinning, and ultimate fiber quality.

At this stage, inspections should focus on:

• Nymphs on the undersides of lower and middle leaves.
• The presence of honeydew around open cotton bolls.
• Whether large numbers of migrating adults are appearing at the edges of the cotton field.
• Whether there are nymphs that have been parasitized or preyed upon.
• Whether current control measures can economically reduce the risk of fiber contamination.

At the same time, it is necessary to strictly verify the PHI (pre-harvest interval), the maximum number of applications, and the harvest schedule.

If harvest is approaching, one should not only consider the speed of insect control but also evaluate actual economic benefits, residue risks, and product label restrictions.

Post-harvest and Field Cleanup

The end of harvest does not mean that whitefly management is completely over.

Якщо на полі є велика кількість пожнивних залишків, порослі та інших рослин-господарів, вони все ще можуть створювати умови для продовження розмноження білокрилок.

In accordance with local agricultural management requirements:

• Promptly dispose of cotton crop residues.
• Control volunteer cotton and regrowth.
• Clear weeds that continue to serve as hosts.
• Monitor whitefly populations on surrounding host crops.
• Prevent whiteflies from continuously migrating between different crops.

These measures help reduce early pest pressure on the next cotton season.

Стадії росту бавовни	Major Whitefly Risks	Пріоритети управління	Candidate Pesticides
Стадія появи та розсади	Adult Migration	Monitor Peripheral Infestations	Evaluate products effective against adult whiteflies based on local conditions
Стадія вегетативного росту	Eggs and early-instar nymphs establish populations	Inspect the undersides of leaves promptly	Select products based on pest population assessment
Стадія бутонізації	Increase in nymph numbers	Focus on surveying nymph proportion	Buprofezin, Pyriproxyfen, etc.
Стадія цвітіння	Simultaneous occurrence of adults and nymphs	Assess population development and natural enemies	Select active ingredients based on the predominant life stage
Cotton boll formation stage	Increased risk of honeydew and sooty mold	Intensify monitoring of pest populations and honeydew	Evaluate appropriate control strategies for nymphs and adults
Cotton boll opening stage	Sticky Cotton Risk	Monitor fiber contamination and harvest scheduling	Make decisions based on local registrations and PHI
Післязбір урожаю	Residual plants and other hosts continue to serve as insect sources	Remove residual hosts from the field	Focus on agricultural management

How to Monitor Cotton Whiteflies and Determine the Optimal Timing for Application?

One of the most important tasks in whitefly management is to regularly survey the undersides of leaves for eggs, nymphs, and adults.

If you only observe the white adults flying above the plants, it is easy to overlook an established nymph population.

How to Conduct a Cotton Aphid Survey in Cotton Fields?

It is recommended to use a fixed survey route and a standardized leaf inspection method to ensure comparability across different survey dates.

The following procedure can be followed:

1. Divide the cotton field into several representative areas.
2. Inspect both the interior and edge areas of the field.
3. Select representative cotton plants.
4. Inspect the undersides of leaves at different positions on the main stem.
5. Use a magnifying glass to observe eggs, early-instar nymphs, and mid-to-late-instar nymphs.
6. Record the number of adults and the proportion of late-instar nymphs.
7. Also observe parasitic wasps, predatory insects, and dead nymphs.
8. Compare survey results periodically to determine trends in the whitefly population.

Throughout the cotton growing season, maintain relatively consistent leaf positions and sampling methods; otherwise, data from different dates may lack comparability.

How should the economic action threshold for whiteflies be interpreted?

Поріг економічних дій використовується для визначення необхідності заходів контролю.

Однак, єдиного, глобально стандартизованого порогу для білокрилок не існує.

Cotton varieties, climate, production costs, survey methods, and harvesting practices may vary across different countries and regions.

For example, the cotton survey guidelines from UC IPM in California use the following regional assessment method:

Survey Criteria	Reference Standards in the California Protocol
Дорослі	Leaves with at least 3 adults are counted as damaged leaves
Late-instar nymphs	Check the undersides of leaves for third- to fourth-instar nymphs
Adult Reference Threshold	40% обстеженого листя відповідають стандарту пошкодження дорослими особинами
Nymph Reference Threshold	40% of surveyed leaves show late-instar nymphs
IGR Application Criteria	The presence of nymphs in the field must also be confirmed

These data are intended solely to illustrate survey and assessment methods for specific regions and should not be used directly as uniform application standards for cotton fields in Africa, the Middle East, Central Asia, or South America.

In actual production, survey methods and thresholds published by the agricultural extension agencies or local cotton management systems of the target country should be adopted.

Why do field edges also require separate surveys?

Whiteflies are capable of long-distance flight, and adult aggregations may appear earlier at field edges.

If nearby cucurbits, vegetables, or other host crops are being harvested, adults may migrate to cotton fields.

Therefore, field surveys should not be limited to the interior of the field.

When pest densities at the field edges are significantly higher than in the interior, the feasibility of localized treatment can be assessed in conjunction with locally registered pesticides and control recommendations.

This approach helps reduce the cost of unnecessary whole-field applications and minimizes the impact on natural enemies in the field.

How can IRAC-based rotation reduce whitefly resistance?

Whiteflies have a strong capacity to develop resistance to pesticides.IRAC data document cases of tobacco whitefly resistance to various insecticide active ingredients, including neonicotinoids, pyrethroids, and certain insect growth regulators.

Therefore, long-term reliance on a single mode of action is not a reliable management strategy.

Why does changing a brand name not equate to changing the mode of action?

Different brand names may use the same active ingredient, or they may use different active ingredients that belong to the same IRAC group.For example:

Активний інгредієнт	Група IRAC	Чи належать вони до різних способів дії?
Ацетаміпрід	4A	-
Імідаклоприд	4A	Немає
Тіаметоксам	4A	Немає
Динотефуран	4A	Немає
Флупірадіфурон	4D	Different subgroups, but cross-resistance still needs to be evaluated
Пірипроксифен	7C	Відрізняється від Групи 4
Бупрофезин	16	Different from Groups 4 and 7C
Спіромесифен	23	Відрізняється від Групи 16
спіротетрамат	23	Same group as Spiromesifen
Біфентрін	3A	Different from other groups

There are two particularly noteworthy details here:

First, Acetamiprid, Imidacloprid, Thiamethoxam, and Dinotefuran all belong to Group 4A. Replacing one of these products does not constitute a complete rotation of modes of action.

Second, although Spiromesifen and Spirotetramat are different active ingredients, they both belong to Group 23 and cannot be rotated as two distinct modes of action.

How to Develop a Reasoned Pesticide Rotation Plan?

A reasoned rotation plan should be based on whitefly generations and cotton growth stages, rather than simply requiring a different pesticide for every application.It is recommended to follow these principles:

• Record the active ingredient and IRAC Group for each application.
• Avoid exposing consecutive whitefly generations to the same mode of action repeatedly.
• Select different yet still effective modes of action based on local resistance monitoring results.
• Consider insecticides used against other pests during the current growing season, as these applications may also exert selective pressure on whiteflies.
• Do not mistake combination products containing active ingredients from the same group for combinations of different modes of action.
• Adhere to the maximum number of applications and application intervals specified on the product label.

For example, Groups 16, 7C, 23, and 4A represent different modes of action and can serve as technical references when establishing a candidate rotation system.

However, this does not mean that all products must be used in a fixed sequence of Group 16 → 7C → 23 → 4A.

Конкретні стратегії ротації слід визначати на основі чутливості місцевих популяцій білокрилки, обсягу реєстрації продукту та рекомендацій IRAC щодо управління стійкістю.

Do combination insecticides always help with resistance management?

Не обов'язково.

Комбіновані продукти можуть допомогти в управлінні стійкістю лише за умови, що кожен активний інгредієнт забезпечує практичну контрольну цінність проти цільового шкідника, а комбінація механізмів дії є розумною.

The following points require special verification:

• Whether each active ingredient is effective against the target whitefly population.
• Whether the two ingredients have different modes of action.
• Whether cross-resistance exists.
• Whether the periods of action for the two ingredients align.
• Чи підходить продукт для бавовни та цільових видів білокрилки.
• Чи відповідає він місцевим вимогам щодо максимальної частоти застосування та використання.

If one of the active ingredients has lost its efficacy, a combination product may not necessarily reduce the risk of resistance.

How can biological control and agronomic practices be combined to manage cotton whiteflies?

Whitefly management should not rely solely on chemical insecticides.

If broad-spectrum insecticides are used in the field over the long term, the population of natural enemies may decline, making it easier for whiteflies to re-establish their populations.

Таким чином, надійний комплексний контроль шкідників (IPM) повинен поєднувати біологічний контроль, агрономічні практики та необхідний хімічний контроль.

Protecting Natural Enemies of Cotton Whiteflies

There are various natural enemies in cotton fields that can help control cotton whitefly populations.

Природні вороги	Англійська назва	Основна роль
Паразитичні оси	Encarsia spp.	Parasitizes whitefly nymphs
Паразитичні оси	Eretmocerus spp.	Parasitize immature whiteflies
Lacewing larvae	Lacewing Larvae	Prey on whiteflies and other small pests
Minute Pirate Bugs	Minute Pirate Bugs	Prey on some whitefly nymphs and other small pests
Lady Beetles	Lady Beetles	Prey on whiteflies and other sucking pests

When developing an insecticide strategy, the impact of the chemicals on these non-target organisms must be considered.

Especially when whitefly populations have not yet reached local control thresholds, unnecessary broad-spectrum applications may disrupt natural control mechanisms.

Reducing Whitefly Infestation Pressure Through Agricultural Measures

Since whiteflies are polyphagous, other crops and weeds surrounding cotton fields must also be managed.

Розглянемо наступний приклад:

• Promptly remove crop residues from harvested host plants.
• Control weeds that can serve as a continuous source of hosts for whiteflies.
• Monitor whitefly populations in nearby vegetable, melon, and other cash crops.
• Плануйте посадку та збирання врожаю відповідно до місцевих умов виробництва.
• Avoid excessive cotton growth and excessive nitrogen fertilizer application.
• Promptly dispose of cotton stubble after harvest to reduce the pest source provided by regrowth.

However, before removing weeds, check for the presence of parasitic wasps and predatory natural enemies to avoid destroying the habitats of beneficial organisms while clearing host plants.

Why Should We Not Rely on Broad-Spectrum Insecticides Too Early?

While some broad-spectrum insecticides can reduce pest populations in the short term, they may also have a significant impact on whitefly natural enemies.

For example, premature or inappropriate use of pyrethroids may destroy natural enemies and increase the risk of outbreaks of secondary pests such as leaf mites and aphids.

Therefore, early management of cotton whiteflies should prioritize monitoring, selective products, and the protection of natural enemies.

Only when field pest populations reach local control thresholds should the need for chemical intervention be further evaluated.

What are the most common mistakes in cotton whitefly control?

поширені помилки	Потенційні проблеми	More Appropriate Management Practices
Observing only adults without checking for nymphs	Ignoring established breeding populations	Regularly inspecting the undersides of leaves
Assuming all insecticides are effective against all life stages	Adults and nymphs may not be controlled simultaneously	Selecting products based on the dominant life stage
Using IGRs as quick knock-down agents	Concluding too early that a product has failed	Evaluate based on the developmental process and subsequent population changes
Continuous use of the same IRAC Group	Increases selective pressure for resistance	Rotate products appropriately based on local resistance status
Switching brands but not active ingredients	Фактичний спосіб дії залишається незмінним	Verify the active ingredient and IRAC group
Ignoring natural enemies	May lead to a resurgence of whiteflies and other pests	Оцінка селективності продукту та нецільових ефектів
Ignoring the risk of honeydew during the boll-opening stage	May cause “Sticky Cotton”	Strengthen monitoring during the open boll stage
Failure to consider the Pre-Harvest Interval (PHI)	Increases risks related to harvest timing and residue compliance	Verify product labels in conjunction with harvest timing

Frequently Asked Questions on Cotton Whitefly Control

Which insecticide is best for controlling cotton whiteflies?

No single insecticide maintains the same level of control across all regions, all cotton growth stages, and all life stages of whiteflies.

Active ingredients such as pyriproxyfen, buprofezin, and spiromesifen are primarily used to manage immature life stages; products such as acetamiprid can be used to manage active populations within the scope of the label.

When selecting a product, consider local whitefly populations, the proportion of life stages, IRAC groups, and product registrations.

Can buprofezin kill adult whiteflies?

Buprofezin belongs to Group 16 and primarily controls nymphs by interfering with chitin biosynthesis and the normal molting process.

It is not an insecticide characterized by rapid knockdown of adults.If the primary field issue is a massive influx of adults while nymph populations are low, it is necessary to reassess whether the product is suitable for the current pest situation.

What is the difference between pyriproxyfen and buprofezin?

Both can be used to manage immature whiteflies, but they have different modes of action.

Пірипроксифен належить до групи 7C і впливає на розвиток дорослих особин, перешкоджаючи розвитку комах та репродуктивним процесам; бупрофезин належить до групи 16 і переважно впливає на нормальну линьку німф.
Therefore, the two are not direct substitutes for one another.

Can Spiromesifen and Spirotetramat be rotated?

It is not recommended to rotate these two as they share the same IRAC mechanism of action.

Although they are different active ingredients, they both belong to Group 23, and their mechanisms of action involve the inhibition of lipid biosynthesis.

Послідовне використання цих двох продуктів може все ще підтримувати тиск відбору щодо резистентності, заснований на тому ж механізмі дії.

Чому бавовняні білокрилки знову з'являються після обробки?

Причин може бути кілька:

• Дорослі білокрилки продовжують мігрувати з інших рослин-господарів поблизу.
• Nymphs on the undersides of leaves were not adequately controlled.
• Insufficient coverage during field spraying.
• Попереднє використання інсектицидів широкого спектру дії знищувало природних ворогів.
• The whitefly population has already developed resistance.
• A large number of eggs and newly hatched nymphs remain after application.

Therefore, it is necessary to reassess the pest situation after application, rather than simply increasing the number of applications.

Що таке «липка вата»? Чому білокрилки спричиняють цю проблему?

“Sticky Cotton” refers to the phenomenon where cotton fibers become sticky after being contaminated by honeydew.

Whiteflies secrete honeydew while feeding on the sap of cotton plants. When honeydew adheres to open cotton bolls and cotton fibers, it can interfere with harvesting, ginning, and spinning processes.

Тому під час стадії розкриття бавовняних коробочок особливу увагу необхідно приділяти популяціям білокрилки та зараженню медвяною росою.

How can we develop a more reliable cotton whitefly control program?

The key to managing cotton mealybugs is not to find a single insecticide that controls all life stages, but to develop a reasonable control strategy based on the mealybug life cycle, cotton growth stages, and local resistance patterns.

First, regularly survey the undersides of leaves for eggs, nymphs, and adults to understand the field population structure.

Second, select appropriate active ingredients based on the predominant life stages. Buprofezin, pyriproxyfen, and spiromesifen can be considered for managing immature life stages, while products such as acetamiprid should be evaluated based on local registrations and target life stages.

Водночас, ротацію слід планувати на основі механізму дії IRAC, щоб уникнути помилкового уявлення про те, що продукти з різними торговими назвами, але що належать до однієї групи, мають різні механізми дії.

Once the cotton boll opening stage begins, honeydew contamination, “Sticky Cotton,” and the pre-harvest interval (PHI) should also be incorporated into management decisions.

For pesticide importers, distributors, and registration companies, when selecting cotton whitefly control products, they should simultaneously evaluate the active ingredients, concentrations, formulations, technical documentation, and target market demand.

If you are developing a portfolio of cotton whitefly control products, we recommend identifying candidate products based on the target country, whitefly populations, primary life stages, and required IRAC modes of action, rather than simply increasing the number of products. POMAIS provides pesticide importers, distributors, registrants, and brand clients with a variety of cotton insecticide product specifications and supporting export documentation.

To evaluate whitefly control products suitable for your target market, please contact our team to further verify the active ingredients, formulation types, product specifications, and supply terms.