Friday, September 7, 2012

Black Bugs All Over Gardenia Blooms

In the late spring and early summer, the gardenia shrub rewards the gardener with an abundance of fragrant blooms.  And as long as they are on the tree, there doesn’t seem to be a problem.  But once the blooms are snipped off and brought into the house, hundreds of tiny black insects called thrips appear.   (It is thrips – whether singular or plural)

These Hawaiian flower thrips are small insects about 1/20 of an inch long, dark brown to black in color. They have piercing-sucking mouthparts which can cause discoloration of the flower petals: they become flecked, spotted, or deformed.  These thrips feed on the flowers, while other thrips can also feed on leaves causing a malformation of the leaf and sometimes even defoliation. Thrips are also a serious pest of coffee, mango, citrus, passionfruit, roses and bananas.

Flower thrips are concealed very tightly within the flower petals of the gardenia. It is difficult for foliar insecticides to penetrate. Using a systemic insecticide, in this case, is more suitable; products with the active ingredient imidacloprid or acephate can be used.  Perhaps a more appropriate solution would be to dip the cut blooms into a bowl of water containing a few drops of liquid dishwashing soap and swishing around. This may not get rid of all the thrips, but it will help.

Gardenias originally came from China.  When a British naturalist received one of these plants in 1761, he named it after his friend Dr. Alexander Garden, a noted botanist and physician in the US.