ORNAMENTALSAND
TURF
ORNAMENTALS
The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
The maple eyespot gall midge, Acericecis ocellaris, is also called the maple leafspot gall midge. The word ocellaris comes from the Latin word ocellus meaning eye (hence the name eyespot gall). An official common name does not exist for this insect. Maple eyespot gall midges emerge in early spring and lay their eggs on the newly-expanding leaves. As the maggots hatch and feed on the tender leaf growth, they secrete substances which cause the leaves to form dimples around the maggots (resulting in striking yellow and red circles around the gall). The maggots soon mature and drop to the soil surface where they evidently dig into the soil to spend the rest of the summer, fall and winter. Another generation of midges will emerge the next year. Insect populations vary from year to year due to weather, predation, diseases and additional factors; thus, the maple eyespot galls may be much less noticeable next year. Because they do negligible damage, their management is not necessary.
Spiny witch-hazel gall aphids, Hamamelistes spinosus, cause bumpy ridges on the leaves of birch. The overwintering eggs are laid on witch-hazel in June and July. These eggs hatch the following spring and the new aphid nymphs crawl to the flower buds to feed; if the plant does not have flower buds, these aphids die! Feeding on the flower buds induces the plant to form a spiny gall. A second generation of winged aphids develop inside the galls, then leave and fly to birch. These winged aphids give birth to a scale- like generation which settles and hibernates on birch until the following spring. As the buds break, the scale-like aphids feed on the leaves and induce the birch to form corrugated galls. Winged aphids that migrate back to witch-hazel or wingless aphids called accessory females develop inside these galls. The winged aphids which migrate back to witch-hazel give birth to a generation of wingless males and females. These wingless aphids mate, and the females lay eggs for overwintering. The special accessory females produce additional generations of winged aphids which migrate to witch-hazel to give birth to males and females that lay eggs for overwintering. Thus, this aphid requires two full years to complete its cycle of life stages. Pesticides should be applied at bud break in early spring to prevent gall formation. It is probably too late this year for effective control. This must be done every year unless the witch-hazels can be found and eliminated. The alternation of hosts is well known for other aphids (woolly apple aphid on apple and elm, woolly alder aphid on maple and alder, and green peach aphid on peach and many other hosts), but the spiny witch-hazel gall aphid seems to have the most complicated life cycle. Ornamentals and Turf Insect Note No. 38 provides information on general aphid management.
Many people this time of year are startled by swollen, curled, light green leaves on their azaleas, rhododendrons, and camellias. These galls are the result of infection by one or more species of the fungus Exobasidium. The diseased leaves later turn white and may develop a powdery surface. Later, secondary fungi move in to cause dark spots, and eventually the entire gall rots away. Fortunately, it will only be a short time before the plant looks good again, and its overall health is not in jeopardy. The grower can pick off the young galls -- the sooner the better -- to reduce the amount of disease that will be seen next spring. Chemical control is not warranted.
Note: Images of early and advanced stages of leaf gall on sasanqua.
There have been many reports the last two weeks of green June beetle grub damage and dead grubs on sidewalks, in carports, etc. Green June beetle grubs are usually only a noticeable problem in turf in late summer through Thanksgiving. However, the high rainfall amounts we have experienced all winter and spring may be causing them to work a little closer to the surface and move more than they normally do in the spring. If they present a significant problem, recommended control measures are still quite effective in the spring as long as night time temperatures remain in the 50's. Activity may continue through the end of May in the western part of the state.
Mole cricket activity has picked up and mating flights should occur during the next two weeks. Spring activity and damage is often at its peak during this time. Remember that control measures directed at the adults are often marginally effective. Control strategies directed at the newly-hatched crickets in late June and early July are most effective.
Fire ant activity is also quite high right now. Spring is a good
time to use baits for control as the workers are actively foraging.
I would anticipate seeing fire ants established in a number of new
sites this year after two consecutive mild winters.
Web page last updated on May 11, 1998 by Stephen J. Toth, Jr..
