English names: Palm Thrips, Melon Thrips
Nordic names: Palmetrips (DK), Palmuripsiäinen (FI), Palmtrips (SE)
Estonian name: Palmiripslane
Major host plants
T. palmi is a polyphagous pest, especially of Cucurbitaceae and Solanaceae, but it has been reported as an outdoor pest of a wide range of herbaceous crops. In glasshouses, economically important hosts are aubergines, Capsicum annuum, chrysanthemums (Dendranthema morifolium), cucumbers, Cyclamen, Ficus and Orchidaceae. Within the EPPO region, T. palmi could infest, for example, Capsicum annuum, cucurbits and ornamentals under glass.
T. palmi, like most species of plant feeding thrips, have piercing and rasping mouthparts. The surface of the leaf develops a crinkled silvery appearance as a result of damage to cells below the surface. Lightly-infested plants show silvery feeding scars on the under surface of leaves, especially alongside the mid rib and veins. Heavily-infested plants show silvering and browning of leaves, stunting of young leaves and terminal growth, with fruit scarred and deformed. Developing leaves become distorced in the growing tips.
A map can be downloaded from EPPO's website. See instructions here.
The eggs of T. palmi are deposited within plant tissues singly. Larvae have two stages, which feed on plant tissues. The second instar larvae, when mature, fall to ground, where they molt to prepupae and pupae in the soil. After emergence, the adults move to the growing parts of the plants such as young leaves, flowers, or young fruits, where they feed and lay eggs (about 200 eggs per female). Adults are usually found on young leaves, while larvae are found on lower or older leaves. At 25°C, the life cycle is completed in approximately 17 days.
T. palmi has only moderate dispersal potential by itself, but is liable to be carried on fruits, art flowers, or plants for planting of host species, or in packing material.
Detection and inspection
T. palmi can be found in pockets, cracks or crevices on host plants. At inspection, silvery feeding scars on the leaf surface, especially alongside the midrib and veins, can be seen. Sticky traps are used for detection. T. palmi may be confused with Thrips tabaci and Thrips flavus. T. palmi adults can only be distinguished with certainty from those of other thrips species by means of laboratory examination.
Pest status and importance
T. palmi, a polyphagous feeder with a wide host range, quickly builds up heavy infestations causing severe injuries. In the EPPO region, T. palmi presents a serious threat to a wide variety of crops grown under glass. It could possibly establish on field crops in southern areas of the EPPO region, as has happened for Frankliniella occidentalis which was originally considered to present a risk only under glass.
Source of information
See further information here:
Author: Christiane Scheel
Editor: Elise T. Yamamoto Buch