Thrips are tiny flying insects that are carried into your garden by the wind on warm sunny days. They are extremely small (about 1/8^th on an inch in length) and they are rarely seen other than in the developing petals of a rose. Most often they are undetected until the rose bud fails to open. Frequently, the edges on the outer petals of the bloom are brown and the petal itself is malformed. The brown discolorations are caused by the insect chewing and sucking the juices of the petal for its nourishment. The best way to deal with thrips is to remove all affected blooms. Dispose of them in a closed bag and directly place it into the trash as to not spread the infestation.

Our efforts to control thrips are enhanced if we understand the life cycle of this insect. Ordinarily a thrip will live between 12 days and about 40 days depending on the weather. In warmer temperatures, the life cycle is shorter. The insects can over winter in weedy areas near your flower beds, and in the leaf litter and soil in your rose beds. In the spring as temperatures warm, the immature adults begin to feed reaching sexual maturity in a few days. The mature female will cut a slit in a developing bud and lay an egg.  In about 3 days a nymph will emerge from the egg and will begin to feed on the tender petals of the unopened bud. The larval stage lasts about 5 days and this is when the most damage to the rose bloom occurs. The next stages is a non-feeding stage and the pupae generally fall to the ground emerging as adults after a few days. Neem oil is one of the deterrents to infestation. Thrips have multiple life stages at the same time, so rigorous culling and destruction of all affected blooms is important.