If you are all year round farmers; then at a certain time of the year, you would certainly have this whitish angelic visitor called whiteflies coming for a visit. It looks as though they come in peace but could turn your farm investment into pieces if their population is not well managed. Come along with me as I unraveled the world of whiteflies and the secret to its management saving you of all your crop farm investment.

Characteristic
Whiteflies are miniature, sap-sucking insects that are often notice when the plant infested is shaken which cause them to fly off. They undergo complex stages of development which often make them to be very difficult to control. All the stages except pupae are parasitic in nature. There are three pre-pupae stages after the eggs called the instars that are difficult to neither notice nor differentiate before the adulthood. They multiply rapidly under favourable condition.
They excrete sticky honeydew and if left unabated would cause yellowing or death of leaves by extension the whole crop in some cases. Honeydew is a liquid rich in sugars. Up to 2,000 nymphs (1st and 2nd instars) may be found on a single bean leaf, each capable of producing 20 drops of honeydew in an hour. Sooty moulds grow on this sugary solution and affect plant photosynthetic property of the plant. Although honeydew helps parasites locate the whitefly, excessive amounts make it difficult for tiny parasitic wasps, such as Encarsia, to walk on these surfaces. The sooty mould that grows on the leaf and fruit surface can significantly affect the appearance and marketability of the crop.


Season of explosion
Whiteflies are common during very dry part of the year as they do not like moisture or wet condition. The reason is that wet condition often affects their flying ability, hence, interrupting their normal trend of development. They develop rapidly in warm weather and when natural enemies are ineffective and when weather and host plants favor outbreaks. Large colonies often develop on the undersides of leaves. Some of the common species such as greenhouse whitefly (Trialeurodes vaporariorum) and sweet potato whitefly (Bemisia tabaci) have a wide host range that includes many weeds and crops. These make them to be difficult to eradicate as most farmers concentrate eradication of whiteflies on their farms whereas another population explosion is occurring on the adjacent non-cropped land whereas the later serves as reservoir for their multiplication and attack-lunching site.
Ants and dust also encourage outbreaks.


Effect of severe infestation and economic losses
This insect looks tiny but causes massive damages if their population and activities are left unabated. The following are the common damages they cause:
- Sucking sap from plants: they suck nutrients rich sap from the phloem (the food-conducting tissues in plant stems and leaves) therefore depriving the host crops of necessary nutrients essential for full productivity. In most cases, this reduces the productivity of the host crops sometimes to zero.
- Uncontrolled, whitefly stunt the growth, reduce yields and can kill a plant by direct feeding, loss of leaf quality and water loss.
- Transmit viral diseases particularly leaf curl virus which can wipe out the whole farm in the case of host crop without certain degree of resistance to the disease.
Read on http://www.hybridveggies.com/2019/01/whiteflies-management-integrated.html