Whiteflies

One of the main pests on rose foliage, whiteflies are small insects (0.9 to 1.1mm), white or pale yellow.  Trialeurodes vaporariorum adults (see fig.1) are characterised by a triangular form and their wings (2 pairs) are covered with fine wax.
By shaking the foliage, adults are well visible but you need some training to detect the eggs, larvae and pupae.

Whieflies can cause direct damages by sucking the sap of crops and producing honeydew. There can also be indirect damages such as the possible transmission of viruses and the development of sooty mold (Cladosporium sphaerosporum).
Proliferation of whiteflies also interferes with the phosynthesis and the respiration.

Eggs are laid on the backside of the leaves (150 to 600 eggs depending on the host plant).

Young larvae are translucent. They can be found on young leaves, whereas old larvae are located on older leaves, often at the foot of the plant.

Once installed, they become motionless and adults emerge from the pupae by a hole. Adults are located at the top of the plants.

The last larval instar is called pupa.

Natural enemies are hymenopterous parasitoids and bugs. Parasitised larvae or pupae become black or yellow, depending on the parasitoid.