For a number of years, the area around the homes located at the upper end of Apple Valley Drive, Sonora, California, have had extraordinary numbers of large, floodwater mosquitoes, genus Aedes (or Ochlerotatus), in the spring. These mosquitoes are larger than the western treehole mosquitoes that are common in the foothills at that time of year. The source of the floodwater mosquitoes has been a mystery, as searching in late spring did not reveal a source. We did a search in mid-April 2017, and found a major breeding area.
Hiking behind the creek, and towards Summer’s Pond, revealed a number of possibilities. Sampling yielded no mosquitoes, except in one location, at what appeared to be a small vernal pool on the edge of thick vegetation (1st photo below). About 100 feet away was what appeared to a second, small vernal pool (2nd photo below). The density of the brush and trees was so great that visibility was highly limited, and these pools did not appear connected. Further investigation revealed that the vegetation was concealing what was actually a gigantic vernal pool, about a quarter of an acre, its perimeter, and center as well, overgrown with thick vegetation. This cryptic, huge pool, hiding in plain sight, contained thousands of mosquito larvae.
The location of the pool is not discernable in the Google Earth 2016 satellite image (38°00’16.49″ N 120°19’32.67″ W), below, but is readily visible in the 1993 image, prior to the tree and shrub growth.
As we do elsewhere, we monitored the frogs, before and after treatment with the mosquito larvicidal oil, and found that the frog population was unaffected.
In addition, we explored a second potential mosquito breeding site, shown in the 1993 satellite image below, by the oval. Sampling on 23 April 2017 did not yield any mosquito larvae, but a number of the larger, floodwater mosquitoes were in the brush area, attempting to bite. This area appears to be directly linked to Summer’s Pond, and is also heavily overgrown. See the images below.
19 April 2017
Mistletoe is a common problem. We are asked, on occasion, about what can be done to control it.
The bottom line is that there is no practical chemical control available currently. The best option is pruning back the mistletoe, and then wrapping it in black plastic for a year.
These are excellent resources:
Although this is early 1990s research, it appears to be the basis for current control methods. Here is a cut and paste of the conclusions of the first paper:
“In conclusion, we found that 10% ethephon applied to mistletoe stubs can be used effectively for mistletoe control in landscape trees. Ethephon appears to be a cost effective, environmentally safe, easy to use and inconspicuous method for mistletoe control. The 10% ethephon treatment would be appropriate on high value landscape trees, or on large scaffolds in combination with pruning of smaller limbs. Black plastic wrapping, while effective, has some possible drawbacks in terms of bark health. Apparently the effectiveness of pruning paint was similar to that of black plastic wrap. More research is needed to confirm the promising preliminary results with pruning paint.”
The chemical they are talking about is a plant growth regulator, Ethephon.
A search, on 19 April 2017, of the California Department of Pesticide Regulation’s site for chemicals approved for mistletoe control shows only one approved material: ACTIVE (03/24/10)NUFARM ETHEPHON 2 PLANT GROWTH REGULATOR ( 228- 660-AA )
It is a category one material, however, a DANGER label. See http://fs1.agrian.com/pdfs/Ethephon_2_Label5.pdf
Florel (https://www.harrells.com/resources/exports/file?n=FLOREL&t=label) has the same active ingredient, ethephon, and a CAUTION label, but is not labeled for mistletoe, and that is likely because it contains only 3.9 percent, versus the 10 percent used in the research. They used Florel Pro in that 1991 research, but Florel Pro is not listed in the CDPR database.
Here is the UC recommendation: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7437.html
But it is an older publication, as Florel is not currently approved for the use.
This article is on track: http://homeguides.sfgate.com/home-remedy-kill-mistletoe-trees-76951.html
Branch removal, pruning back the mistletoe, and then the use of the black plastic wrap may be the better option, as you won’t have the chemical hazard, and related regulatory hassles, to deal with.
A customer on Lime Rock Road, near Sonora California, reported bites from buffalo gnats. She collected specimens from a light fixture for us. In addition to numerous gnats and beetles, there were, indeed, a number of black flies. Specimens collected 13 April 2017. Thank to Dr. Lynn Kimsey for ID confirmation.
The source could well be Sullivan Creek, as it is within flight distance of black flies, although any stream can serve as a breeding site. The flight range can be five miles, although most, in one study, traveled 1.5 miles. (source: “Flight range, longevity, and habitat preference of female Simulium euryadminiculum Davies (Diptera: Simuliidae“)
These large, red and black carpenter ants are very common in the lower elevations, in the oak woodland areas.
These ants are nocturnal, foraging at night. They do not excavate wood, which is common for many other carpenter ants. I have found colonies of these ants under rolled carpet, between sheets of stacked plywood, under rocks, at the base of live oak trees, and under the foil layer of fiberglass attic insulation. In one case, the ants were between the insulation that was cut out to fit over an attic access door, and the adjoining insulation over the ceiling, and they fell on me as I opened the attic door. Maybe the oddest nest location I have seen was on the inside wall of a large drainage pipe, after removing the manhole cover; the ants were simply holding onto the inside of the large pipe. So, these ants do little in the way of nest construction. Their large size, sometimes within and adjacent to human habitation nest locations, and large size, make them particularly annoying pests. The distribution range seems connected to the interior live oak areas.
On 7 May 2016, I retrieved a large caterpillar from a valley oak tree. I attempted to raise it, but the caterpillar died in the cocoon stage. Dr. Lynn Kimsey (thanks!) identified it as a Pacific tent caterpillar, Malacosoma constricta. It was a solo individual, and no netting or tenting was seen. Below are photos of the frass and the caterpillar. For image of moth, see this page.
Distribution of the Pacific Tent Caterpillar