Cuban laurel thrips (Gynaikothrips icorum) have been reported as
a serious problem in interiorscape plantings of Indian laurel in
Houston, Dallas and other metropolitan areas. Control is
difficult because of the limited number of products registered
for use in interiorscapes, lack of proper timing of insecticide
applications needed to prevent serious damage, and lack of
adequate coverage required to control the population after damage
has already occurred.
Adult and nymphal thrips feed on the upper surface of young and expanding leaves, causing reddish feeding scars along the midribs of the leaves. Leaves in the process of unfolding become deformed and tightly curled and folded, appearing crescent- shaped. Damaged leaves first turn reddish, then dark brown and hardened before dropping from the plants. Besides causing the plant to look unsightly and defoliated, infestations slow plant growth. Nymphal populations develop in colonies inside of the tightly curled leaves.
Plants should be inspected regularly, particularly during growth periods in the spring and fall. If Cuban laurel thrips are detected, treatments should be initiated to protect developing foliage. The damage threshold has been reported to be two thrips per leaf. Bendiocarb (Dycarb®, Turcam®), a nonsystemic carbamate insecticide, has been reported to provide good control of Cuban laurel thrips one week after application. Oxamyl (Oxamyl® 1OG), a granular formulated systemic insecticide, was reported to provide control near the damage threshold for six weeks (Reinert, 1983). Outdoors,acephate, chlorpyrifos and methidathion have been used successfully, although these materials are not registered for use in the interiorscape.
Treatments must be applied to protect leaves from thrips feeding while they are expanding. Once damage has occurred and nymphal thrips populations are developing in tightly curled leaves, adequate coverage with insecticides to reach these protected targets is extremely difficult. Systemic insecticides are generally not taken up by plants when they are not actively growing, and will not move into dead or dying leaves. Thus, management of the Cuban laurel thrips is essentially preventative, although treatments should be timed to growth phases of the host plant when thrips are first detected.
Reinert, J.A. 1983. Controlling Cuban laurel thrips in nurseries and landscapes. American Nurseryman 157 (8):63-66.
The USER is always responsible for the effects of pesticide residues on his livestock and crops, as well as problems that could arise from drift or movement of the pesticide from his property to that of others. Always read and follow carefully the instructions on the container label.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.
Educational programs conducted by the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin.
1990
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Last modified: March 18, 1997 by Edgar Cross