Below is the letter being distributed to Borough residents by our network of Block Captains. If you haven’t received your letter, feel free to download it here: MayorHerrin_OutreachLetter_2018. A doorhanger with concrete suggestions on how to fight off mosquitoes will follow later. If you’d like to help us by becoming a Block Captain, see here.
On May 29, John Jackson (BA in biology, MA in zoology, PhD in entomology) spoke on having a weed-free sidewalk and neutralizing mosquito breeding spots without using harmful chemicals. His talk at Iron Works Church in West Chester was sponsored by Don’t Spray Me! / Sierra Club and the South West Association of Neighbors (SWAN).
Here are some highlights of his talk and the subsequent discussion (with some resorting of topics):
Mosquitoes are the best-known insects in the world, because of their role in spreading diseases, especially malaria, yellow fever, and dengue. But the ways chemical tools have been overused against them are not in the interest of either people or wildlife. Chemicals may be needed to prevent massive epidemics, especially in the tropics, but when overused become ineffective because insects develop resistance.
There are lots of biting flies beyond mosquitoes. Here, the predominantly evening-biting Culex mosquitoes can carry West Nile Virus but day-biting Aedes (including Asian Tiger, which has been in the US only since 1985) almost never do. People should not view all insects (of which most don’t bite) as enemies.
Culex, the “house mosquito,” overwinters as adults in sheds, porches, tree hollows, and other sheltered areas. The adult mosquitoes we see in May have overwintered; they may have not yet had time to reproduce. Culex mosquitoes love urban environments, where they lay eggs in water where larvae feed on bacteria and organic matter.
West Nile Virus, which came to the US in 1999, depends on birds as a reservoir (unlike Zika, whose reservoir is people, making it easier to contain, as recently in Miami). Some birds, which in the past were often dying of WNV, appear now to be developing immunity. Fortunately, WNV is not transmitted through mosquito eggs, only from a bitten bird to another bitten bird or human. Known human WNV cases have been rare in PA.
Effective non-chemical defenses include tight-fitting screens, fans on ceilings or porches, repellents (notably lemon eucalyptus oil, picaridin, or citronella oil), various odoriferous granules spread in gardens or lawns.
Fogging with pesticides is a bad idea, because it kills many species, including mosquito predators like spiders; drift cannot be controlled; and it kills only adult mosquitoes, whereas many more larvae are just waiting to hatch every day and take over the air space.
The absolutely most important thing is to eliminate standing water, including where we might not think of it: in plastic bottles, the folds of tarps, in the fixed bottoms under some potted plants, even vases in cemeteries.
From mosquito egg to adult probably takes 10-15 days when weather is hot and damp, but 25-30 days with temperatures in the 70’s.
The bacteria-based larvcide Bti is very effective at killing mosquito larvae. The biscuits and granules have slower release than liquid and powder form. The hormonal Methoprene is also not toxic and prevents the metamorphosis to adult.
One of the worst sampling stations is in SE West Chester; it is not clear if that is related to Goose Creek. Trash in suburban streams creates mosquito habitat. And water can stand in old storm sewer lines like the Borough’s.
Some undesired plants, like dandelions and poison ivy, are best dug up. Weeds are tough, but weakening them by cutting off the leaves a few times makes them more vulnerable to other treatments.
Old-school boiling water works really well; be careful, wear boots and goggles! Ditto butane flame torches. Or: a weak acid breaks down cell walls; vinegar works, but changes the soil chemistry.
He prefers to use 1 cup of borax (another kind of salt) in 1 gallon of warm water to kill weeds. The borax concentration can be doubled if needed. It also, for better or worse, it also kills ants, moss, lichen, and liverwort. Two applications a summer usually suffice, preferably in hot dry weather, since rain washes the borax away.
Regular table salt also kills plants; witness the die-off this past winter along roads and alleys in the Borough, which uses salt and brine to melt snow and ice. Municipalities tend to use twice as much salt as 20 years ago, even though less harmful substances are available. As a result, streams have increased chloride levels; he measured half the salt content of seawater in one stream.
First, we got some good coverage in 2017 (as in 2016) in the Daily Local News. See “Area teens find organic solution for killing weeds in sidewalks,” 7/17/17, and “‘Don’t Spray Me!’ holds rally in West Chester,” 8/28/17.
Our 5-page report can be downloaded here: DSM report 2017 12-3-17. It includes the following topics:
Spraying, larviciding, and storm drains
West Chester got through another summer with no Chester County Health Department spraying, but East Bradford, Downingtown, Birmingham, Thornbury, and Spring City were not so fortunate. It was a difficult summer with heat and lots of rain and in some areas residents reported more mosquitoes than in 2016.
We would like to emphasize preventive measures and are pressing for more thorough-going inspection, repair, and larviciding of storm drains wherever they exist. We believe that storm drains and sluggish natural water in dry weather are now the main sources of mosquitoes here. We plan to continue to emphasize the Block Captain model in West Chester.
East Bradford report
Lots of progress coming from the town’s Environmental Advisory Council and municipal staff; and residents and homeowner associations started to be more active.
Other accomplishments and victories in 2017
– a March for the Environment, following speakers in the center of West Chester, with 250 people
– an experiment in which our “Sierra Club Youth Corps” of high school students showed that a non-toxic solution is effective in fighting weeds in brick sidewalks
– two celebratory community picnics in May and in September, with other local groups
– an environmental film series at West Chester University in the fall, emphasizing toxic chemicals
Goals for 2018
Work with municipalities and the County on community education.
Emphasize larviciding, the most effective form of mosquito control.
Understand better the Vector Index used as a guide to spraying by the County and work toward raised thresholds.
Institute an “Adopt a Storm Drain” program.
Start up new DSM chapters.
A new model of yard signs.
Programs: Jan. 21 environmental justice film, Feb. 25 panel on environmental and climate change, Earth Day gathering and march on Sunday April 22, summer community event, May and Sept. celebrations in Everhart Park, Green Lawns event in fall.
A summer intern helping implement outreach, mosquito control, and larviciding goals.
In the 4-part mosquito life cycle*, the most vulnerable stage is the larva. Eggs are designed to survive, pupae don’t eat and their chief enemy would be rough water preventing them from breathing, and adults as we all observe are elusive fliers.
But larvae depend on feeding on organic matter in unclean standing water. If they get too hot or cold, don’t find enough food, or can’t breathe regularly at the surface, they will develop into adults either slowly or not at all. Continue reading
As often happens in mid-summer, mosquito traps set by the County are starting to show some West Nile virus positives. This means that at certain trap sites, over a 24-hour period, one or more mosquitoes out of the scores or hundreds trapped were carrying the virus.
No humans are known to have been affected so far in Chester County, but this means we citizens should redouble our efforts to curb the mosquito population and fend off spraying, whose harmful effects are known and whose benefits, if any, are unproven beyond the initial destruction of adult insects of all species.
Two West Nile Virus positives this month have occurred at Greenfield Park at S. Franklin St.,and Greenview Alley, West Chester, just south of E. Nields St., in West Chester, ward 4, in the southeast part of the Borough
Also, there have been positives in a couple of other sites around the County.
To do your part, please refer to “What can I do to reduce the mosquito population?” and the concrete advice on the Borough site’s Mosquito Awareness page about suppressing standing water.
In West Chester, Block Captains should by now have distributed both 1) a letter from Mayor Jordan Norley and 2) a doorhanger from the Borough.
If you live outside West Chester Borough, please contact us and we will put you in touch with others in your community.
Please examine closely:
Potential mosquito breeding ground, right? Nice dirty stagnant water, gathering at the bottom of a bulkhead to be pumped out.
Can mosquitoes fly in? Certainly; no bulkhead is constructed tight enough to keep out a small insect.
Has the homeowner taken the right precautions?
Yes! Note the Bti larvicide tablet floating on the left side. Very good!
Thanks to the East Bradford municipal administration for giving their residents useful guidelines for protection against breeding and being bitten by mosquitoes. The article below is from page 6 of the East Bradford summer 2017 newsletter.
In addition, East Bradford’s Environmental Advisory Council (EAC) has prepared further information which you can download at the EAC site, including a very thorough In-Depth Report and a Summary.
DSM wishes East Bradford residents as mosquito-free summer as possible!
If you spot a pile of tires exposed to precipitation, please let us know. Tires, whether old or new, are mosquitoes’ best breeding territory, because they warm up in the sun and hold water long-term invisible to human eyes. N.b. in West Chester, tires should be stored inside, not outside.
Excerpt from “What Tire Pile Owners Should Know About West Nile Virus” download at PA DEP:
Could a tire pile be a mosquito-breeding site?
Tire piles could provide suitable areas for mosquitoes to live, including those known to carry WNV. When discarded tires are allowed to accumulate even a small amount of water, they become attractive sites for mosquitoes to lay their eggs. For example, during the course of one season, thousands of mosquitoes can emerge from just one tire. If tires infested with mosquito eggs, larvae or pupae are transported, the potential to spread mosquito populations increases. This is one of the theories on how WNV was introduced into the United States.
How can a property owner prevent mosquito breeding?
It is the responsibility of the tire pile owners to make sure that the pile does not create a nuisance or health hazard. There are a number of ways to eliminate mosquito production in tire piles.
Standing water in the tires should be eliminated. This can be accomplished by properly storing tires under a tarp or other cover, removing the side wall, or drilling holes in the back of the tire.
In situations where eliminating mosquito production areas is not a practical alternative, larviciding is the most effective control technique….
read the full download here: Tire piles 3800-FS-DEP2535
by Nathaniel Smith, The Times of Chester County, 9/1/16
Getting rid of standing water is more effective than spraying
News has come around lately that “Pennsylvania Is Now One Of The Top States With Zika Virus ” (Phoenixville Patch, 8/23/16). Currently PA ranks 5th in the number of diagnosed Zika cases. Of course, no one knows how many undiagnosed cases there are anywhere.
Quick quiz: how is Zika spread? If you answered “by mosquitoes,” you’re only half right. It’s our fault too.
It’s important to focus on this note in the article: “All of the cases were travel-related, according to the Centers for Disease Control and Prevention.”
That means no human has acquired Zika from a mosquito in PA. Although the prime mosquito host for Zika, aedes aegypti, does exist in Pennsylvania, it doesn’t do well this far north (yet).
The fact is that Zika is spread not only by mosquitoes but also by people, whether through sexual contact (CDC offers explicit advice on this aspect) or from carrying the virus (usually without symptoms) and being bitten by a mosquito that in turn bites someone else, who thus acquires the disease. The aedes albopictus mosquito, often called “Asian tiger,” has become very numerous in PA but fortunately does not seem to transmit Zika very well (yet).
Spraying pesticides is a limited, short-term fix that leaves many adult mosquitoes alive and does not affect eggs and larvae but harms many forms of life and can lead to acquired immunity. Mosquitoes breed over 500 times faster than people, so they will become immune to whatever we do against them much faster than we can evolve to resist them. Mosquitoes in Puerto Rico and Florida are already becoming resistant to permethrin, the standard anti-mosquito pesticide.
This is all not good news, except that in PA we do have some time to get ready for present and future mosquito-borne diseases….
read more at The Times of Chester County
by Melissa Breyer, treehugger, April 8, 2016
A new study found this cheap, easy system significantly reduced virus-carrying Aedes mosquitoes in Guatemala.
Called an ovillanta, a simple mosquito trap fashioned from old tires spells doom for mosquito eggs. So effective is the cheap eco-friendly system that during a 10-month study in Guatemala, the team collected and destroyed over 18,100 Aedes mosquito eggs per month, almost seven times the eggs collected compared to standard traps. Anecdotally, the researchers note that there were no new reports of dengue during the time in the area, normally during that timeframe the community would have reported up to three dozen cases.
The Aedes genus of mosquitoes is primarily responsible for transmitting a host of vexing viruses, including Zika, dengue, chikungunya, and yellow fever. Aedes is notoriously tough to control, according to the World Health Organization. Pesticide-resistance, lack of resources, and a boost in mosquito-friendly environments have hindered traditional methods of controlling the pest’s quick spread.
Created in collaboration by researchers from Canada and Mexico, the ovillanta is made of two 20-inch sections of old car tire secured together in the form of a mouth, with a fluid release valve at the bottom. A milky mosquito-luring non-toxic solution is poured in the bottom – the solution includes a mosquito pheromone that tells female mosquitoes that it’s a safe place to lay eggs. The mosquitoes enter, lay eggs on a paper or wooden strip that is floating in the “pond” … twice a week the little egg raft is removed, the eggs destroyed, and the solution drained and filtered before being reused in the trap again….
read more at treehugger