Page 123 - ORNAMENTALES DEL TRÓPICO

123
identiFication and management oF ornamental Pests

host plant becomes undesirable, winged aphids are produced that will establish new colonies.
Many aphids are specialists feeding on only one or a few closely related host plants. Aphids

remove plant fluid with their piercing mouthpart which can be damaging to the plant, howe-

ver, their ability to transmit plant virus diseases may be more harmful than any direct feeding

damage. Feeding damage can cause the leaves to curl or crinkle and flower buds to become

hard which causes flower distortion. Aphids secrete large amounts of honeydew. They are

commonly found on plant stems, undersides of leaves and in flower buds. Although most aphids

have the same overall appearance, there can be exceptions. For example, the palm aphid which

is a common pest of palms does not look like a typical aphid but more like a scale insect.

Whiteflies resemble tiny white moths however, they are more closely related to scale
insects. The immature stages are found on the underside of leaves and are flat, oval and very

small. They are usually light green to whitish and sometimes transparent. The host range varies

greatly with different whitefly species. Both adults and immatures feed on the leaves of plants

but it is the immature stages that cause the most damage. Feeding causes reduced plant vigor

and leaves display yellowing or chlorosis. Heavy infestations can cause a plant to wilt and even-

tually die. The immature stages also excrete large amounts of honeydew.

b. Thrips

Thrips are small, elongate, cylindrical, gregarious insects ranging from 1/25 to 1/8 inch. The

nymphs are frequently pale yellow and are highly active. Adults are usually black or brown but

may have red, black or white markings. The adults are winged but the wings are long, narrow

and fringed with hairs. Thrips attack an extremely wide variety of plants. Thrips feed on the
foliage, flowers, as well as young tissues of new growth. Feeding causes bleached, silvered or

deformed leaves and necrotic spots or blotches on flowers.

Universidad Autónoma de Chiapas