|Cliff Sadof, Entomologist
The following article will appear in the next issue of Down the Garden Path (#165).
Bugged by spotted or distorted leaves, dying flowers, distorted fruits and vegetables? Well you just may be bugged by true plant bugs. Plant bugs have been causing quite a few problems throughout Indiana landscapes. When plant bugs feed they juices from expanding young leaves or flower bud, they can kill portions of actively growing tissue and distort leaves, flowers and fruit. On expanded leaves plant bugs remove the green chlorophyll from leaves, leaving them to appear stippled with white spots when the plant bug has removed sap from green leaf tissue that contains chlorophyll. Some species kill portions of leaf tissue as they feed and leave behind circular areas of brown dead spots. The liquid excrement of most plant bugs is deposited as a black tar spot that is diagnostic for many pest species.
Although many natural enemies of plant bugs are known, their use has not been explored for controlling this pest on deciduous trees. Pesticide applications should target nymphs because eggs are not affected. Determine this stage by looking for spiny nymphs near egg masses on leaf undersides and monitoring to determine egg hatch. Short residual materials, like soaps, oils, or pyrethrins, can be effective on nymphs if coverage is adequate. Systemic pesticides such as Orthene (Acephate) or Merit (imidacloprid) are also very effective. Topical foliar applied materials can also provide effective control.
Yucca bug image courtesy of Charles Felkner
|Some common plant bugs:
PLANT DISTORTERS PART ATTACKED HOST KEY ID FEATURE Honey locust plant bug leaves honeylocust lime green Tarnished plant bug flowers & fruit fruit trees, brownish lilac, many others Potato leaf hopper leaves red maples, lime green many others PRODUCERS OF BROWN SPOTS PART ATTACKED HOST KEY ID FEATURE Four-lined plant bug Leaves Many perennials, Yellow & black shrubs stripes PRODUCERS OF PART ATTACKED HOST KEY ID FEATURE WHITE STIPPLES Yucca bug Leaves Yuccas Orange & brown (Adam's Needle, etc.) Eastern ash plant bugs Leaves Ash Amber color Lace bugs Leaves Many species Lacey wings
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Last updated: 3 July 2000/tlm.