BGYL 9726

	October 1, 1997	From: Pam Bennett, Joe Boggs, Jim Chatfield Gary Gao, Jane Martin, and Randy Zondag

This is the 26th 1997 edition of the Buckeye Yard and Garden Line (BYGL). BYGL is developed from a Tuesday morning conference call of Extension agents, specialists and other contributors. This conference is then summarized by the seven writers listed above and e-mailed to Extension offices in Ohio, Indiana, Kentucky and Pennsylvania.

BYGL is also made available via the Internet on PENpages and The Ohio State University (OSU) Department of Horticulture and Crop Science and Ohio Department of Natural Resources, Division of Forestry Web sites. A number of Extension offices throughout Ohio offer FAX subscriptions to the green industry.

BYGL is a service of OSU Extension and is aided by major support from the Ohio Nursery and Landscape Association (ONLA), with additional funding from the Ohio Chapter of the International Society of Arboriculture (ISA) to the OSU Extension Nursery, Landscape, and Turf Team (ENLTT). ONLA, Ohio Chapter ISA, and Ohio Turfgrass Foundation members are not charged for FAX subscriptions.

Participants in the September 30 conference included: Pam Bennett (Clark), Joe Boggs (Hamilton), Jim Chatfield (Northeast District/Horticulture & Crop Science), Erik Draper (Mahoning), (Dave Dyke (Geauga), Gary Gao (Clermont), Mimi Rose (Horticulture and Crop Science), Nancy Taylor (Plant and Pest Diagnostic Clinic), and Randy Zondag (Lake). .

	BYGLBreak	Each year in October, BYGLers become so dog-gone tired that we go to a biweekly rather than weekly schedule, as the season and plant observations begin to slacken off somewhat. So it is again, this year: THERE WILL BE NO BUCKEYE YARD & GARDEN LINE NEXT WEEK. We will return with the next BYGL on October 16, followed by the annual Evaluation survey on October 23, and the final BYGL on October 30, if it is deemed useful.
	WEATHERWATCH	"Dry" is the word around most of the state except for an isolated area in the northeast. Dave Dyke reported that they were getting quite a bit of rain on Tuesday. However, everyone else was waiting on Joe Boggs to "make his own weather." (See BYGL 97-25). Joe noted that the Cincinnati area experienced its 5th driest September since records have been kept with a total of 0.51 inches of precipitation. And of course, "Randall of Arabia," (not to be upstaged) said, "You've had a lot more rain than we have!" Temperatures have been in the low to mid 70's during the daytime so plant stresses due to dry weather aren't as bad as they could be. Lawns, however, are somewhat dormant and if core aeration is being planned, be sure to irrigate thoroughly first.
	FALL FOLIAGE	As we move into October, fall foliage features are beginning to emerge in a pleasant way, not simply as premature fall coloration that can signal plant stress. In northeast Ohio, the sumacs are beginning to exhibit scarlet inner and lower foliage while the outer and most exposed foliage remains green, making for an attractive contrast. Sour gums at Secrest Arboretum in Wooster are now about half and half between glossy green and glossy red leaves. Finally, one more reminder that inner needle yellowing and browning of evergreens continues to excite the curiosity and concern of observers. Up to a point, this is normal, unless more years than usual of older needles are affected for a particular species, in which case the phenomenon is much like early fall coloration on deciduous trees - a sign of stress.

	TAR SPOT OF MAPLE	This is one of the many minor late-season leaf spots on trees and shrubs in the landscape. Though the tarry black spots (sometimes nickel-size or larger) are quite spectacular, they are not generally considered significant to plant health.
	CEDAR QUINCE RUST ON JUNIPER	We usually talk about cedar quince rust on its most common rosaceous host in Ohio - hawthorn. Nancy Taylor reminds us that, in some cases, this disease causes considerable problems on its other host - juniper (Eastern red cedar). Nancy has received numerous samples this year of Juniperus scopulorum cv. Wichita Blue with considerable branch dieback from this disease. The dieback was enough to make the plant quite unattractive.

	MIMOSA WEBWORM: TOO LATE TO SPRAY	Several BYGLers reported that "special spray programs" are currently being offered in their locales for controlling third generation mimosa webworm on honeylocusts. This is a bit like Napoleon Bonaparte drawing-up battle plans for Waterloo while living in exile on the island of Saint Helena...it's too late, the battle is over! Webworms cover leaflets with thick webbing and larvae feed within the protective confines of these structures. Although nests constructed by early instar larvae can be penetrated with insecticides, the dense nests currently being found throughout much of Ohio will not be effectively infiltrated by spray materials. At best, the sprays are a waste of money since larvae may remain untouched by the chemicals. At worst, the spray materials can kill bio-allies such as damsel bugs (see BYGL 97-18), which may offer some effective long-term relief from mimosa webworms. Also, as with Napoleon's ultimate fate, the honeylocust leaflets currently being consumed by the webworm are about to be sent into permanent exile.
	BLACK VINE WEEVIL	Randy Zondag noted that black vine weevil adults are still being found in northeast Ohio. While this nursery/landscape pest of taxus, rhododendrons, and over 100 other plants, may remain active into late fall, control efforts are usually focused only on the summer months. The summer applications target adults in an effort to reduce egg production. Of course, eggs give rise to larvae which is the most destructive and difficult to control stage of this insect. It is getting late for applications since early instar larval progeny of these adults may not survive the winter. However, given the uncertainty of winter weather conditions and the availability of winter shelter in some nurseries (e.g. polyhouses), applications should continue as long as adults are present. See OSU FactSheet HYG-2016-95, "Black Vine Weevil (and other root weevils)," for a complete discussion of management strategies for this insect.
	"REGULAR" MITES	Randy also reported that "warm season" mites (active in the summer), such as two-spotted spider mites, are on the decline while "cool season" mites (active in the spring and fall), such as spruce spider mites, are on the rise in northeast Ohio. Spruce spider mite activity and damage is often only associated with the spring and control efforts are often only focused on controlling these early season populations. However, in Ohio, populations are typically higher in the fall and a significant amount of damage is seen in association with this late season activity. Conifers such as spruces, pines, firs, Douglasfir, etc., should be closely monitored now to avoid late season damage. Landscapers should look closely since there is a cool season eriophyid mite which may cause similar damage on spruce (see item "D" below).
	"IRREGULAR" MITES: ERIOPHYIDS	Mimi Rose observed severe "bronzing" on baldcypress in her research plots caused by an eriophyid "rust" mite. Similar damage on baldcypress caused by an eriophyid rust mite was observed in northern Kentucky this year and last year by Mike Klahr (Horticulture Agent, University of Kentucky, Cooperative Extension Service, Boone County). In both cases, a positive identification of the eriophyid mite was not made. However, Mimi is getting a sample to various mite experts in the Department of Entomology at Ohio State to see if a positive I.D. can be made. Stay tuned! Randy Zondag noted that hemlock is also coming under attack from another eriophyid mite. The hemlock rust mite (Nalepella tsugifolia) seems a likely candidate. This eriophyid behaves as a cool season mite in that populations and damage are typically high in the spring and fall. Feeding activity causes the foliage to turn blue-green then reddish-brown and high populations may cause heavy defoliation of hemlocks. Another eriophyid mite, Nalepella halourga (no common name), may cause bronzing of inner needles in the fall on Colorado blue spruce. In 1994, Rayanne Lehman (Entomologist, Pennsylvania Dept. of Agriculture) sent the following information (first printed in BYGL 24-21) relative to a BYGL report regarding inner-needle discoloration on Colorado blue spruce: "Several years ago we had a similar problem in a nursery in PA. Eventually, the interior needles turned brown and dropped from the tree. The problem was not spruce spider mite but "spruce rust mite", Nalepella halourga. This eriophyid rust mite is closely related to hemlock rust mite, Nalepella tsugifolia, but is restricted to spruce. Just like hemlock rust mite, it is a "cool season" pest and hatches even earlier than the spruce spider mite. Fall populations should be starting to increase soon and the mites will remain active until late November." "The overwintering eggs are red and deposited on the needles on the underside of the branch. They are usually deposited in groups, on the basal 1/3 of the needle. The eggs are rather small, about the size of the stomata."
	GRASS BAGWORMS	As reported earlier this season in BYGL 97-11, grass bagworms do exist and they are now attaching themselves to various structures in southwest Ohio. These moth larvae should not be confused with the common bagworm (Thyridopteryx ephemeraeformis) which has completed its larval feeding activity for this season and can be found hanging on various trees and shrubs. The following is from the earlier BYGL report: "Unlike it's larger, spindle-shaped relative, grass bagworm is a tiny caterpillar that feeds on grass. It constructs a diminutive, one-inch long, silk bag with bits of grass blades attached. No serious damage is done to turf, and no control is needed. When ready to pupate, the larvae attach their bags to fences or siding. They may also congregate on structures during periods of heavy rain, making them a nuisance pest."
	LEAFFOOTED BUGS ARE KNOCKING AT THE DOOR	Erik Draper reported that leaffooted bugs are becoming a nuisance in homes in northeast Ohio. Adults of the western pine cone leaffooted bug are searching for overwintering sites. The one-half to three-fourths inch long, brown insects spend their evening hours buzzing around porch lights and occasionally they find their way into homes. These insects get their name from the flat, leaf-like structures found near the end of the hind legs. The western pine cone bug prefers Scotch, pitch, and red pine cones. Homes near high concentrations of these trees may be more likely to experience a visit from this footloose nomad. Although adults have unusually long sucking mouthparts, they are not a threat to homeowners. Control of this and other soon-to-be-seen winter vagrants (e.g. boxelder bug) depends primarily upon exclusion. Caulking cracks around windows frames, checking for loose screens and gaps in door jams will reduce entry points into the home.
	ARACHNID-ERRORS	Several BYGLers noted that spider populations are exploding throughout the state. This is not unusual since many species overwinter as eggs and females are now busy spinning webs and converting the essence of their trapped prey into egg masses. Aside from a few well known miscreants (e.g. black widows, brown recluses), most spiders should offer little concern to homeowners. In fact, given that spiders are the "vampires" of the Arthropod-sphere (they suck the juices from their hapless victims), spiders definitely fall into the category of bio-ally in our efforts to manage insects. Although this point may do little to qualm a raging case of arachniphobia, it should at least provide some help in suppressing over-reactions to their presence. However, BYGLers occasionally come across a case of arachnidabuse that simply defies a logical explanation. Erik Draper reported receiving a phone call from a landscaper who asked for his assistance in identifying insects "all over a white pine." Erik examined the pine tree and could find no insects, only a health population of spiders. When he reported his observations to the landscaper a short time later, he was surprised (nay, shocked!) to learn that in the mean time, the landscaper had sprayed the tree. Erik asked why and the landscaper replied, "just on general principles." BYGLers on the conference call vented a collective exasperated sigh...or perhaps they were simply making a symbolic effort to waft away the cobwebs of ignorance...
	BYGLOSOPHY	With the weather-making capabilities of some BYGLers being revealed for the first time last week, the following quote seems appropriate: "We should be never content until man makes his own weather and keeps it to himself." -- Jerome K. Jerome
	Where trade names are used, no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears the responsibility of consulting the pesticide label and adhering to those directions. All Ohio State University Extension educational programs are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability, or Vietnam-era veteran status.

Return to Search Index