Beetle alert!

Tuesday, March 1, 2011

An orchid-eating beetle.

Spring, it appears, has arrived early. And with warm, dry weather come beetles and thrips.  Sitting brazenly atop a light lavender cattleya hybrid today was a black beetle with some light spots on its back. Two more beetles were on the adjacent flower. They’ve been emerging like crazy as the soil warms up, and we’re finding them by the bucket load in the pool skimmer. The larvae are grubs that have pupated in the soil, munching away on grass roots.

Damaged tissue is black, found
on the lip tissue at the base
of the column.

Having found three, I examined all the light lavender and white cattleyas to see what harm they had done. They typically like to crawl down into the throat of a large cattleya (or white or yellow rose) and eat. Damage is to the lip enfolding the base of the column or the column itself. Yes, the signs were there, but confined to a small group of flowers in one area of our shade house.

So what to do? Place a white bucket of plain water next to the flowers. I did, and within 10 minutes there was a beetle doing the backstroke. They are attracted to white, and will fly into the bucket and drown.

Thrips, which are tiny black sucking insects, love mango and avocado blossoms as well as orchid flowers.  Vanda flower buds are especially vulnerable, so spray with Orthene, a systemic insecticide.