Sir, may be due to indiscriminately usage of synthetic pyrethroids in early stage of the crop cause the resurgence of the sucking pests (Hormologosis).

Dear Praful Ashokrao Malthankar Primarily. The death of natural enemies from the use of insecticides. Also, if high soil moisture is favorable for increasing the number of this species. Regards, Sergey Viktorovich Pushkin

Hello, how are you? First I would like to thank you for the consultation. From my experience in tomato and pepper the excessive use of agrochemicals generates. 1) that the plague begins to have resistance and 2) destroy the natural enemies that are more sensitive to agrochemicals. Both points generate an increase in population and if you add to this that you have optimal environmental conditions for the development of the pest, such as the variable temperature and humidity, this increase in the pest in the crop can occur

Cotton plants are usually subject to the attacks of several insect pests from seedling germination till harvest

Bemicia population (nymphs and adults) on the cotton plants seedling stage in (April – July)

the life cycle varied mainly depending upon (three factors) the temperature, relative humidity and the host plant

that enable it to (1) cause severe damage through plant feeding (sucking the sap) and (2) transmit more than 90 types of virus diseases

The two predators

Ch. carnea and C. undecimpunctata

and the endoparasitoid Ecrimocers for management of cotton pests

The main purpose of IPM programs is to minimize the usage of conventional insecticides hoping to reduce environmental pollution and toxic effects on the natural enemies

Thanks a lot for your informative answers Rajashekhar Mandla, Pushkin Sergey Viktorovich, Sovit Parajuli, Jorge Eduardo Castresana and Essam ossman Tabozada.

The population of whitefly may be also affected and increased by the rate of nitrogen fertilization and planting date.

The flactuation of temperature and humidity are the most factors that effecting on the increasing of Whitefly population , in addition of the absence of natural enemies. Best regards

Hello, all ecological factors (including Density-Independent and Density-dependent Factors) can influence on population development of whitefly. You should check what's changed in the environment. Good luck!

I have experienced a surge of population of whiteflies in the green house on cotton. It is obvious that greenhouses have a higher humidity and temperature. Mine lacked proper ventilation and no temperature control :(

It is also very difficult to control whiteflies using pesticides in such a situation.

I have a great experience dealing with cotton pests during my Ph.D. and hereafter. I can assure that increasing of R.H.%, mild temp. and the absence of predators especially the big-eyed bug due to extensive use of insecticides are the factors responsible of the sudden increase in B. tabaci populations.

I agree with eminent Jorge Eduardo Castresana.

Indiscriminate use of insecticides cause insecticide resistance among cotton insect pests and destruction of bioagents population cause high pest:defender ratio due to shortage of food chain, and results sudden increase of cotton insect pests outbreaks.

fluctuation in abiotic factor may important role esp. temperature and humidity. use of sub lethal and over dose of insecticides.

at the end of cotton season the adults migrate to the other hosts i.e. malvaceous plants and abiotic factor such as temperature, realative humidity, scanty rainfall...etc.

The surge of B. tabaci could be due toi several factors:

- Loss of sensitivity to insecticides

- Effect of insecticides on natural enemies

- emergence of new species

- Decrease of rainfall observed on recent years in Ivorian cotton area

- If the cotton is GMO, secondary pest outbreaks may occur

- Environmental factors due to the absence of natural enemies

After preceptation Prolong absence of rainfall and increasing the temperature to favour with whitefly population build up and causes severe damage

1. Resistance

2. Abiotic Factors flactuation

3. Limited Crop Rotation

4. Absence or reduction in natural enemies

5. Its High Fertility during stress.

Yellow sticky traps should help

May be due to:

3. less rainfall

4. temperatur increase

5. succeptible cotton variety planted . . .

Abiotic factors are more important including broad spectrum insecticide spraying

1. Indiscriminate use of synthetic pyrethroids

2.Destruction of natural enemies

3. abiotic factors fluctuation

The morphological characters of plants also playing a major role in the pest population surge. In the case of cotton the trichome density also a reason for whitefly survival. More number (Dense) of trichomes will restricting the egg laying of whiteflies on the surface of cotton leaves. If your cotton plant having less number of trichomes means it will help for the whiteflies survival and egg laying.

Abundance of an insect species are due to measures of success under the effect of the sum total of physical and natural environmental conditions such as weather, physical and chemical conditions of the medium, food, enemies, competition and various control measures (physical, chemical or biological) undertaken. In instances, a number of conditions will be favorable and others unfavorable for the increase of the species. However, if favorable numbers predominate, then the insects multiply to outbreak numbers which might have happened in case of sudden increase in the population of white flies on cotton plant.

In general the sucking pest population increase if the temperature is high, besides may be the reason of resistance development against insecticides or unavailability of natural enemies population.

High relative humidity coupled with temperature or sudden raise of temperature following rainfall may be the possible reason for the sudden rise or development of insecticidal resistance