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HomeMy WebLinkAboutMINUTES - 07071987 - 2.5 TO BOARD OF SUPERVISORS FROM: Phil Batchelor, County Administrator Contra DATE: July 7, 1987 Costa SUBJECT: Report on Activities of the Contra Costa Mosquito County Abatement District SPECIFIC REQUEST(S) OR RECOMMENDATION(.S) & BACKGROUND AND JUSTIFICATION RECOMMENDATION Accept attached report from Superintendent, Contra Costa Mosquito Abatement District, on the recent outbreak of mosquitoes at the Martinez Regional Shoreline Park and on the District' s 1987 Program. BACKGROUND On June 2, 1987, Supervisor Nancy Fanden brought to the Board' s attention a recent infestation of mosquitoes which occurred in the downtown Martinez area. The Board requested our office to obtain a report from the Contra Costa Mosquito Abatement District on that incident and on the District' s activities in general. Our staff contacted Mr. Charles Beesley, District Manager. Mr. Beesley has submitted the attached report with the understanding that he will personally appear before the Board if additional information is desired. CONTINUED ON ATTACHMENT: _ YES SIGNATURE: RECOMMENDATION OF COUNTY ADMINISTRATOR RECOMMENDATIO OF O COMMITTEE APPROVE OTHER SIGNATURE(S): ACTION OF BOARD ON July 7 1987 APPROVED AS RECOMMENDED X OTHER VOTE OF SUPERVISORS 1 HEREBY CERTIFY THAT THIS IS A TRUE X UNANIMOUS (ABSENT I, IV AND CORRECT COPY OF AN ACTION TAKEN AYES' NOES: AND ENTERED ON THE MINUTES OF THE BOARD ABSENT: ABSTAIN: OF SUPERVISORS ON THE DATE SHOWN, CC: County Administrator ATTESTED `/ /9 PHIL BATC LOR, CLERK OF THE BOARD OF SUPERVISORS AND COUNTY ADMINISTRATOR M382/7-83 BY DEPUTY 00 CONTRA COSTA DOARDOFTRUSTEES MOSQUITO ABATEMENT DISTRICT ADMINISTRATION PRESIDENT 1330 CONCORD AVENUE MANAGER Ston Husted Charles Beesley, Ph.D. Son Ramon CONCORD, CALIFORNIA 94520 (4151685-9301 VICE PRESIDENT [8001 331-8321 Guy Kelley Brentwood SECRETARY Contra Costa County Freda Ericksen Pleasant Hill UN'I1�I t� 19 ANTIOCH J 2 G 98 Charles T. Mozzei JUNE 17, 1987 CLAYTON Office of Margaret E. Gipps Mr. Gary Brown County Administrator Deputy County Administrator CONCORD 651 Pine Street, 11th Floor Earl W. Mortenson Martinez, CA 94553 COUNTY AT LARGE Richard H. Bortke Dear Gary: Patricia Bello Alan Deaner On ca. May 27, 1987, an outbreak of mosquitoes RichardE F. Peters Doccurred at the Martinez Regional Shoreline Park . The Richard Contra Costa Mosquito Abatement District became aware ELCERRITO of the severity of the outbreak by the numerous Dr. Sedgwick Mead service requests we received on June 1, 1987. HERCULES Bruce J. Holmes It is rare that a mosquito source of this size LAFAYETTE gets off undetected by one of our zone operators. Marilyn Milby They inspect marsh areas monthly 3-10 days following the highest tide focusing on known problem areas . The MARTINEZ Dr. Ronald Wheeler Martinez Regional Shoreline Park has historically not been a problem area. By the time our operator MORAGA inspected the park area in his cycle the species of Kenneth L. Moehler mosquito in question had already emerged into adults ORINDA creating the infestation. The outbreak was magnified Darrel W. Harris by the fact that the species of mosquito involved PINOLE bites during the day, unlike the majority of the Thomas L. Lease mosquito species in this county. Also the proximity of the outbreak to the city of Martinez added attention PITTSBURG to this isolated incident . Vacant RICHMOND On June 2 adult landing counts were taken by Sondra Beyoert district personnel to document the problem and SAN PABLO determine necessary action. Eleven stations were Vacant designated., An average of 12. 36 adults landing in a WALNUT CREEK one minute period was realized. Based on this data Nancy Brownfield and the habitat involved we adulticided the park on June 3. Landing counts of only 0. 54 were taken on June 4 indicating an effective reduction of adults of over 95%. On June 5, Bill Nichols, the parks supervisor, advised us that the infestation seemed to be returning. Landing counts on June 6 confirmed his impression with counts averaging 5. 3 in an expanded focus area. On June 7 we again adulticided expanding our focus to the marsh area west of the park . Adult counts on June 8 averaged 0. 78 at 24 stations. Again MEMBER CALIFORNIA MOSQUITO,AND VECTOR CONTROL ASSOCIATION CONTRA COSTA ADMINISTRATION BOARD OF TRUSTEES MOSQUITO ABATEMENT DISTRICT MANAGER PRESIDENT 1330 CONCORD AVENUE Charles Beesley, Ph.D. Stan Husted CONCORD, CALIFORNIA 94520 Son Ramon (415) 685-9301 VICE PRESIDENT (E300) 331-8321 Guy Kelley Brentwood SECRETARY Fredo Ericksen Pleasant Hill this data showed that the treatment effectively ANTIOCH reduced the adult population by 85%. On June 12 heavy Charles T.Mozzei mosquito breeding was noted by our operator and a CLAYTON district crew larvicided the marsh on June 16. Margaret E. Gipps Throughout this incident much labor and materials CONCORD were used including overtime by several district Earl W. Mortenson employees. We anticipate this area to be a chronic COUNTY AT LARGE mosquito source until the drainage problem is Richard H. Bortke corrected. Land use of this area has changed in the Patricia Bello Alan Deaner past few years creating a situation were water is allowed to enter the park on high tides with no means DANVILLE of draining back into the strait . Mr . Nichols has Richard F. Peters been cooperative and is working with our personnel in EL CERRITO developing plans to rectify this situation. Dr. Sedgwick Mead HERCULES Bruce J. Holmes Xery tr 1 LAFAYETTE Marilyn Milby u� MARTINEZ Dr. Ronald Wheeler Craig W. Downs Superintendent MORAGA Kenneth L. Moehler enclosures ORINDA Darrel W. Harris PINOLE Thomas L. Lease PITTSBURG Vacant RICHMOND Sandra Beyoert SAN PABLO Vacant WALNUT CREEK Nancy Brownfield MEMBER CALIFORNIA MOSQUITO AND VECTOR CONTROL ASSOCIATION _CONTRA COSTA MOSQUITO ABATEMENT DISTRICT DISTRICT PROGRAM 1987 SOURCES There are nine major sources of mosquitoes within the District: marshes, rainwater, catch basins, tree-holes, ornamental ponds, artificial containers, drains and creeks. These sources and District control efforts are briefly outlined as follows: Marshes are found along the coast from Antioch to Richmond and are subject to periodic flooding from rainfall or tidal action. This flooding often results in emergence of . daytime-biting salt marsh mosquitoes. These are strong flying insects which can affect recreation, industry and residential areas. The District' s long term commitment to preventive control programs through installation and maintenance of recirculation ditches, tidegates and pumphouses has resulted in effective mosquito control in these sources. Recirculation ditches have been found to be environmentally sound and provide a good habitat for mosquitofish, thereby enhancing biological control of mosquitoes in the marshes. Pastures are predominantly found in the eastern part of the county. These sources are subject to intermittent flood irrigation which often results in emergence of daytime and evening biting mosquitoes. The former are moderate daytime fliers which can affect agriculture, recreation and residential areas. The latter are more local in their distribution but can also have similar impact. Both types of mosquitoes are capable of transmitting encephalitis. The District stresses water management, specifically three day irrigation cycles or less, coupled with pesticide applications to csontrol these mosquiotoes. Sources will vary from year to year according to land use and irrigation practices. • Rainwater results in seasonal emergence of high numbers of mosquitoes in the spring and summer. These mosquitoes may transmit encephalitis as well as being pests , thereby necessitating a high control priority. Sources will vary with annual rainfall and are spread throughout the county. The amount of rainfall also affects the underground water table, in turn affecting creek flow and mosquito emergence during spring, summer and fall. 1 Catch basins or storm drains are found throughout the county but mosquito production is usually associated with older, flatter parts of communities, often in the downtown areas. Street water-runoff accumulates in these basins and their connecting underground pipes as a result of land settling and/or debris. Mosquitoes emerging from them are very attracted to lights, frequently enter houses, and often affect an entire residential area. Tree-hole mosquitoes emerge April through July but rarely fly over 300 yards. Homes situated in the foothills with large oak trees are the most affected by this mosquito. In the past, control has been achieved with pesticide applications in individual tree holes. This is very labor intensive and costly, and due to limited manpower has been discontinued. The District still recommends tree-surgery or filling in the holes by property owners. These mosquitoes also transmit dog heartworm which is noticeably increasing in the San Francisco Bay area. Ornamental- ponds are found in virtually all neighborhoods, and can be controlled equally with chemical or biological control. The District stresses routine filtering and cleaning of ponds. When appropriate, mosquitofish can be stocked in ponds and are available to the public at the District Office in Concord. Current program restrictions do not include individual backyard control; however the District keeps records of service requests, should control efforts be required. Artificial containers are found throughout the county and include items such as oak barrels, buckets, wheel barrows, flower pots, etc. Any container which holds water for 2-3 weeks can be a source of mosquitoes. Although these are on private property and are the responsibility of the homeowner, neighborhoods can experience mosquito problems for some time before the source is found and water is cleaned or removed. Drains are found along many streets and are either concrete lined or earth ditches and are designed to direct surface water runoff to storm drains and eventually the creeks. Oftentimes they become clogged with debris, silt-up or level out which results in standing water, weed growth and mosquito production. Road pollution is often high and prevents stocking with fish. Creeks for all intents and purposes are inland flood zones : 2 drying up completely, intermittently or not at all. The extent of drying varies per creek and per season relative to temperature, rainfall, underground water table and street-water runoff. There are about 1200 of these sources in the District, because water flow varies so much they are under constant surveillance and control activity. Inland creeks are the single greatest source or habitat for mosquitoes in the District and the most hazardous to inspect and treat. They are often inaccessible, deep and riddled with debris or overgrown with poison oak, blackberries, and other trees and shrubs. In many residential areas, backyard fences encroach over creeks making it nearly impossible to walk the entire length of the creek causing double entries and frequent back-tracking for the field operator. New residential projects expand housing along creeks, increasing the need for District field surveillance and control. Current District control efforts are centered around chemical applications supplemented with occasional stocking of mosquitofish. 3 MAJOR SOURCES OF MOSQUITOES IN CONTRA COSTA AND COMPARISON OF CONTROL METHODS DISTRICT SOURCE PRIMARY SECONDARY EFFORTS Marsh Physical Biological/Chemical All three Pastures Chemical Physical . Both Rainwater Chemical Biological Both Catch Basins Physical Chemical Chemical Tree Holes Physical Chemical Chemical Ornamental Biological Chemical Biological Ponds Artifical Physical Chemical Advisory Containers Drains Chemical Biological Both Creeks Chemical Biological Both 4