Sunday | June 26, 2016
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Stink bugs can plague okra plants

Aloha Garden Guy. We have wonderful weather in Kapoho to grow okra. But some kind of bug loves to leave okra with little bumps. Any idea what bug? Any solutions? I suspect it may be stink bugs but haven’t seen any on the pods. Thanks for your wonderful advice. — Susan

Okra fruit as well as leaves and flowers are susceptible to the Southern green stink bug. Damage is achieved by inserting their needle-like mouthpart into the plant tissue and sucking out the plant juices. Some stink bugs can cause wart-like growths as the plant reacts to the piercing. To confirm, a number of the pests should be visible when feeding on the okra, although their green color blends with the foliage making them difficult to find. The adults are active fliers and when disturbed will fly away or fall towards the ground.

Control is sometimes difficult. Horticultural oils, including Neem oil, work well, but the solution needs to contact the insect. To spray when the insect is not there will do no good. Oil, as well as soap, is contact insecticides. The harsher chemicals like Sevin and Orthene will also control this pest.

In many areas biological control is effective and chemical control is seldom necessary. In Hawaii, introduced parasites (good guys) are well established and are generally effective. Predators include spiders and the big headed ant. The ants prey upon the eggs and immature stages, taking them back to their nests. The stink bug is so named because of the strong odor emitted from scent glands when disturbed.

Hello Garden Guy! I researched info on the kamani tree. The trees are recently being infested by the white fly. Do you have any suggestions of how to cure the tree to enable it to regrow its upper canopy? From what I’ve read, it seems like the best natural cure is heavy mulch of sawdust, wood shavings, bark and other organic material around the base of the plants out to the drip line to conserve soil moisture. The spiraling whitefly removes plant fluids and increases moisture loss, therefore, the trees will require additional soil moisture to prevent wilting. — Michael W.

You are correct that an insect infestation will cause trees to loose moisture as they suck out the juices, and mulching will help the tree conserve water, especially in times of drought. A little fertilizer will help, too. But that alone is only a short-term measure. In the long run, biocontrol should do the trick.

In general, kamani trees don’t have many pests, particularly, those that cause real damage. However, from the pictures, you do have some whitefly and possible scale insects attacking the tree.

Repeated applications of an oil or soap spray will help. You can also choose an insect growth regulator. Yet, since the tree is big, spray applications will be difficult. You may, therefore, prefer to use a product with the active ingredient imidocloprid. This is a systemic insecticide that is applied to the ground for root uptake, or sprayed on the foliage.

Since even this may be an expensive and a sizable task, and since kamani trees resist attacking insects to some degree, biocontrol may be the best solution. Let the natural enemies come in and do their job. One major factor which hampers good biological control is the presence of ants. If present, they will need to be eliminated; ant baits can be effective.

Hilo resident Nick Sakovich is a professor emeritus of the University of California. He has worked in the field of agriculture for 30 years. Email your questions to Sakovich at


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