An Integrated Insect Control Program for Street Trees
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AN INTEGRATED INSECT CONTROL PROGRAM FOR STREET TREES W.OLKOWSK1 * C.PINNOCK * W.TONEY * G.MOSHER W. NEASBITT . R. VAN DEN BOSCH * H. OLKOWSKI Over the last three years the Recreation and OST STREET TREES are not native were brought under control by the follow- Parks Department of the City of Berkeley to the region in which they are ing five species of parasitic wasps: (1) plantedM and are therefore subject to oc- Trioxys curvicaudus Aphidiidae and (2) has worked with members of the Department casional invasions by insects that be- Mesidiopsis subflavescens Aphelinidae, of Entomological Sciences, University of Cali- long to exotic ecosystems. Often a plant- both from France and Italy; (3) Mesidi- fornia, Berkeley, to develop an integrated feeding insect invades an area that lacks opsis subflavescens Aphelinidae, from insect control program for the city's 30,000 the beneficial insects which would serve as Czechoslovakia; (4) Trioxys pallidus natural controls on the invading species. Aphididae, from Holland; and (5) M. street trees. The program has virtually elimi- The frequent result is an abnormally high subflavescens Aphelinidae from Italy. nated synthetic chemical insecticides as population which natural enemies in the These wasps reduced the aphid popula- regular management tools on the city's 123 invaded system cannot control. Such in- tion to the point where insecticides have sect problems may be permanently solved become unnecessary. Since these host- species of shade trees. This program has by classical biological control, which in- specific parasitic wasps have overwin- resulted in lower pest management costs, volves determining the native area of the tered and propagated themselves, no other fewer citizen complaints, elimination of pest, a searching in that area for its control efforts are anticipated. secondary pest outbreaks and a reduction natural enemies (parasites and preda- Many species of caterpillar, including tors), identifying the carnivores, select- California oakworm (Phryganidia cali- in environmental contamination. By reducing ing candidates for importation, collecting fornica), may be safely and selectively the amount of pesticides used, the city of and shipping them, subjecting them to controlled by Bacillus thuringiensis Berkeley saves about $22,500 each year in quarantine processing (where all but the sprays. This spray is available in several commercial formulations, some of which labor and pesticide costs. The current pro- desired new species are destroyed) and finally, colonizing the imported natural were used for oakworm control in 1969 gram is a synthesis of various non-toxic man- enemies on specific host insects. This pro- by the California Division of Highways agement methods including biological, cedure was successfully followed for three and by the City of Berkeley in 1970. Be- microbial, cultural, physical-along with the species of aphids (Eucallipterus tiliae, cause B. thuringirnsis kills only caterpil- Tinocallis platani. Tuberculoides annu- lars, no harm is caused to the beneficial judicious use of chemical controls, when latus), which attacked linden, elm and insects, birds and animals that provide needed. English oak trees, respectively. They biological control of other potential pests. UALIFORNIA AGRICULTURE Single copies of these publications-except Manuals Progress Reports of Agricultural Research, ond books-or a catalog of Agricultural Publications published monthly by the University of Cali- may be obtained without charge from the local office fornia Division of Agricultnral Sciences. of the Farm Advisor or by addressing a reqvest to: William W. Paul ............. .Mianuger Agricultural Publications Agricultural Publications, University of California, Jerry Lester ................... .Editor Berkeley, California 94720. When ordering sale items, Linda Brubaker .........Assistant Editor please enclose payment. Make checks or money orders California Agriculture Publications payable to The Regents of the University of California. Articles published herein may be republished or reprinted provided no advertisement for a commercial product is implied or imprinted. SALTON: Please credit: University of California uc A New Cultivar of Alfalfa Division of Agricultural Sciences for Low Desert Valley Areas of South- California Agriculture will be sent free upon request addressed to: Editor California ern California. Bulletin 864. This publi- POWDERY MILDEW DISEASE OF GRAPE- Aorieulture. A oriculturad Publi&tionn. TJni- ve"rsity of California, Berkeley, California cation describes a new alfalfa cultivar VINES. Leaflet 212. This publication de- 94720. Notify same office for change of addressaddress. which resists the low desert valley sum- scribes the effects of powdery mildew on To simolifvsimplify the information in CuEifornio I mer disease complex. It is also re- grapes. It describes the life cycle of the AgricultuieAgriculture 6it is sometimes necessary to use trade names of products or equipment. No sistant to the spotted alfalfa aphid bio- fungus, conditions favorable to its spread, endorsement of named products is intended nor is criticism implied of similar products type Ent F and to the pea aphid, but is and methods of control and eradication which are not mentioned. expected to be susceptible to most leaf in both table grape and wine or raisin <y&* 141 and stem diseases. grape vineyards. CALIFORNIA AGRICULTURE, JANUARY, 1974 3 Water sprays about 100 were treated. In the futurc High pressure water spraying was sub- this number will probably be reducec stituted for insecticides on elm, English still further by spot treatment of suscep oak, birch, pyracantha, plum, scarlet tible trees only. oak, beech, ash and big leaf maple. With Another important aspect of the pro Injuence o trees greater than 30 ft in height, line gram was the care to respond to citizen: pressures were increased to 600 psi to who called the Recreation and Parks De permit coverage of the highest parts of partment about pest problems. Staff mem the infested portions of trees. Some large bers contacted them directly and througk trees were only partially sprayed to re- written information sheets to explain thf move localized infestations. Disadvan- department’s pest management decisions tages of this technique include the possi- These steps frequently helped such per bility of severe leaf removal by the spray sons adapt during difficult periods wher on lower portions of trees, fraying of honeydew drip was excessive. foliage and excessive mortality to bene- Inspection at the complaint site usually ficial insects. However. through proper reveals one of three situations: (1) plan1 seasonal timing and adjustment of line damage, (2) honeydew contamination. pressures, water spraying is an extremely or (3) annoying insect populations. In useful, inexpensive and harmless pest con- the Berkeley study, priority lists for re. HE DEPTH at which asparagus trol technique. peated monitoring were developed with crowns are placed in the soil or are direct-seededT varies in California be- Adhesive hands plant-damaging insects first, then honey. dew producers, and finally the annoyance tween production areas and between The Argentine ant (Iridomyrmex hu- problems. Depending on severity of the growers in a single area. The influence of milis) occurs on most street trees in complaint, number of plants involved, different seeding depths on asparagus Berkeley and is associated with all of and the investigator’s judgment, par production has not been clear. Some the pest aphid species. In many cases ticular problems were monitored anc studies show that ridging increases yields. I. humilis increases population levels of additional studies were undertaken. These studies do not specify the depth honeydew producers, especially aphids, These studies helped to sort out the po- of soil cover over the plants, however. by interfering with beneficial insect popu- tential biological control candidates from lations. When aphid and ant populations This report summarizes the progress of those that could be managed otherwise. are excessive, sticky adhesive bands of both field and lathhouse studies initiated “Stickem” (1 inch wide, and 1/8 inch In the three years Berkeley has had in 1969 to determine the effects of plant- thick about 5 ft above ground) around this program, pesticide costs have ing depth on the production of green as- tree trunks exclude ants and reduce aphid dropped, regular calendar spraying of paragus. Results were judged in terms of populations. This barrier is effective dur- large numbers of trees has been elimi- earliness of production, yield as measured ing spring, summer and fall, and al- nated, complaints from citizens have been by number and weight of spears, and though unsightly to some people, captures reduced, and an efficient organized ap- spear size. many insects, particularly flies. It also proach to solving a complex management Asparagus Var. 72 was direct-seeded stops the passage of predators that have problem has evolved. into the bottoms of preformed furrows fallen from trees, but provides a non- 2, 6, and 12 inches in depth. The plant- toxic aphid control and ant management William Olkowski is Assistant Re- ings were made in double rows per bed at tool useful in urban areas. search Entomologist, Division of Bwlog- a seeding rate of 40,000 seeds per acre in Since many of Berkeley’s pest aphids ical Control; Dudley Pinnock is Assis- May of 1969. The two rows were spaced prefer the inner portions of host trees tant Insect