Santa Clara County officials announced Thursday that an invasive mosquito species was found at a fourth location in San Jose, in response to a news release.

The Aedes aegypti mosquito is a non-native species known for aggressive biting in the course of the day and may transmit various diseases. The mosquito was found at six locations throughout Santa Clara County. It was most recently present in San Jose around Cortez Avenue and Orlando Drive.

“The threat of Aedes aegypti is increasing, and we must all help now to prevent this day-biting mosquito from establishing itself in Santa Clara County,” said Edgar Nolasco, director of the Santa Clara County Department of Consumer Affairs and Environmental Protection. “In the interest of public health, businesses and residents must check their properties for standing water sources and remove them. And we need people living in areas where this invasive mosquito has been found to work with county staff and give them the opportunity to inspect their properties.”

The mosquito is a few quarter of an inch in size and will be identified by the black and white stripes on its back and legs. They are likely to feed only on humans and stay inside about 500 feet of their birthplace.

The mosquito was found at locations in San Jose near Oak Hill Funeral Home and Memorial Park, in addition to in Santa Clara, Gilroy and East San Jose. County officials attributed the increased mosquito activity to warmer temperatures brought on by climate change.

Authorities said Aedes aegypti mosquitoes persist in 19 California counties, primarily within the Central Valley and Southern California. However, the presence of the mosquitoes is observed but not proven in 4 Bay Area counties.

District officials warned that the mosquito can transmit diseases corresponding to dengue, chikungunya, Zika and yellow fever. In 2024, the Los Angeles County Department of Public Health reported 12 cases of locally acquired dengue.

Aedes aegypti mosquitoes don’t require much water to breed and are likely to lay eggs just above the water line in small, man-made water sources corresponding to buckets, pet bowls, fountains and birdbaths, flower pots and saucers, and old tires. In dry conditions the eggs can survive for greater than a 12 months.

The county's efforts to forestall the establishment of a everlasting population of the invasive mosquitoes include trapping adult mosquitoes, inspecting properties to search out mosquito larvae and habitats, and treating any identified larvae with pesticides.

The county said it might soon treat the world around Cortez Avenue and Orlando Drive with a series of large-scale larvicide sprays conducted with truck-mounted equipment; Officials would also use mosquito control treatments on adults if crucial. The county has previously sprayed pesticides in neighborhoods where mosquitoes potentially carrying West Nile virus were found.

County officials advised residents to guard themselves from mosquito bites by applying insect repellent, wearing long-sleeved shirts, pants, socks and shoes on days when mosquitoes are most lively, and ensuring window and door screens are in good condition.

They also beneficial that rain barrels, cisterns and irrigation canals be properly screened to forestall mosquito access. repairing leaky faucets and broken sprinkler heads; Avoiding overwatering of lawns and plants; Remove standing water and ensure water levels in swimming pools allow for correct circulation and filtration. Residents were also instructed to wash and scrub all containers with hot soapy water or bleach to remove any Aedes aegypti eggs and to permit them to dry for no less than a day.

As county officials visit neighborhoods to treat mosquitoes, they advised residents to permit staff access to their properties for inspection and treatment and to report day-biting mosquitoes to the Vector Control District at 408-918-4770 or vectorinfo@cep.sccgov.org .

The county's Vector Control District will hold a community meeting at Anthony Dorsa Elementary School, 1290 Bal Harbor Way in San Jose, on November 18 at 6:30 p.m.

Originally published: November 14, 2024 at 3:59 pm PST

When we went to an aspen forest near Madison, Wisconsin, with a colleague within the spring of 2021, we expected to finalize our plans for a research project on several species of insects that live in and feed on the trees. Instead, we found a forest full of furry, brown egg masses.

These masses, belonging to an invasive species called the gypsy moth, brought our plans to an abrupt end. We knew that hungry gypsy moth caterpillars would eat the forest bare inside weeks.

We are chemical ecologists interested in how plant chemistry affects the interactions between plants and herbivorous insects. As experienced scientists, we all know that sometimes good science stories end very in another way than researchers originally expected. This is one in every of those stories. And like many good stories, it involves villains, beauty, poison, and death.

After an initial period of despair over the fate of our aspen forest, we modified our research plans to research how leaf loss – one other word for leaf consumption – by an invasive species might alter the chemical composition of plants to the detriment of native species.

All Plants produce defense substances to ward off herbivores resembling insects that attempt to eat them. These defenses include well-known chemicals resembling tannins, caffeine, and cyanide. Insects, in turn, have evolved adaptations to those chemical defenses which are tailored to the particular species they feed on.

The results of this study surprised even us and published in September 2023 within the journal Ecology and Evolution.

The ecological actors

Aspen () is the most typical tree species in North America.

As a keystone species, the aspen provides food and shelter for a lot of forest organisms. Without these trees, forests across much of North America would look very different. The aspen is ecologically successful, partly due to its unique chemistry. It produces a category of Defense substances, so-called salicinoidsUnder most conditions, these defense mechanisms prevent herbivores from completely defoliating trees.

Invasive gypsy moths () are essentially the most destructive defoliators of deciduous forests in North America. Aspen is a preferred food plant of the gypsy mothwhich feed on expanding leaves in early summer. At high population densities, gypsy moths can defoliate large areas of forest.

This carnage brought on by the gypsy moth doesn’t bode well for other insects that rely on aspens for food, resembling the native silkworm, which feeds on aspens from mid to late summer.

A natural experiment

From May to June 2021, the caterpillars of the gypsy moth ate almost every green leaf in our aspen forest.

At the start of July, nevertheless, the trees had full leaves again. In a second aspen forest of the identical age, six kilometers away, there was no leaf shed.

This combination of damaged and undamaged forests provided the proper conditions for what scientists call a natural experiment. The undamaged forests served as an experimental control that we could compare to the damaged forest to evaluate the implications of leaf shedding by the gypsy moth on insects that feed on them in late summer.

We collected leaves from each forests in late summer and analyzed them for his or her salicinoid content.

We also fed the native Polyphemus caterpillars with leaves from the defoliated forest or from control forests to see how the defense substances affected their ability to survive and grow.

We found that After defoliation by gypsy moths, aspens grew a second set of leaves with significantly higher salicinoid levels—on average 8.4 times higher. In contrast, leaves from the control forest had significantly lower salicinoid levels, typical for aspens in late summer.

The high concentrations of defense substances within the defoliated forest caused severe damage to the native silkworm caterpillars. Only just a few caterpillars survived when fed with leaves from the previously defoliated forest. Those that survived showed growth disorders.

Ecological impacts

Our research has shown for the primary time how an invasive species can harm a native species by making their shared food source rather more toxic. And one of these ecological dynamic is probably going not limited to only aspen and silkworm caterpillars.

Over 100 different species of insects and mammals feed on aspen trees. our previous research has shown that top concentrations of salicinoids are harmful to lots of them. Other tree species resembling oak also produce more defensive substances after the gypsy moth sheds its leaves, which could affect native herbivores.

Insects are crucial for the functioning and prosperity of all terrestrial ecosystems. Yet scientists are observing that their numbers and variety are declining worldwide. This phenomenon is generally known as Insect apocalypse.

The The reasons for this decline are manifolddiverse and removed from fully understood. Research like this helps to shut this gap. Plant toxin-mediated indirect effects of invasive species seem like one other cut within the Death by a thousand cuts from insects everywhere in the world.

Finally, our story is a story of science in motion. Scientists cannot fully anticipate how natural events can disrupt the best-laid research plans, especially in field projects. Floods, droughts, tornadoes, lightning strikes, insect plagues—our research groups have experienced all of them.

But sometimes researchers meet these challenges with creative ingenuity and scientific adaptability, and this will result in surprising breakthroughs in our understanding of this extraordinary world.

In their latest try and eradicate an invasive mosquito species discovered last month, Santa Clara County officials will spray an east San Jose neighborhood with a bacterial spray next week.

Since early April, district officials have discovered 12 female Aedes aegypti mosquitoes in a residential area near Machado Lane, off Story Road. These mosquitoes are invasive in the world and may transmit various diseases, similar to Zika, dengue fever, yellow fever or chikungunya. Zika will be especially dangerous for pregnant women, as it may cause birth defects and problems for the newborn.

“It's a challenge, but we're trying our best to make sure this mosquito doesn't take hold,” Nayer Zahiri, director of the Santa Clara County Vector Control District, said at a news conference Friday.

On Wednesday morning, authorities said they may spray the world with a pesticide that controls the mosquitoes' larvae. The treatment, referred to as a large-scale larvicidal spray, takes two hours and is derived from naturally occurring bacteria which are nontoxic to humans, helpful insects and other wildlife. The county plans to spray the world several times over the subsequent few months.

Zahiri said the threat from the mosquitoes stays low and that the rare cases of Aedes aegypti-related illness within the county have come from individuals who have traveled to places where the mosquito is endemic or established. Since April, the issue area has expanded to about 118 acres of the East San Jose neighborhood and includes greater than 250 properties, said Noor Tietze, scientific technical services manager for the Santa Clara County Vector Control District.

County officials previously responded to the infestation with surveillance efforts, with staff setting traps along Machado Lane, inspecting properties for mosquito larvae and standing water, and removing any larvae.

Two of the invasive pests were found on the Newby Island Landfill in Santa Clara County in October 2022 and were quickly eradicated.

But the recent infestation in a residential area is harder to eradicate, said Edgar Nolasco, director of the Santa Clara County Department of Consumer and Environmental Protection. According to a county news release, more mosquitoes were present in an area with a whole lot of people – and ahead of the warmest months of the 12 months when mosquitoes are more energetic.

“Controlling the population is not easy because the Aedes aegypti mosquito adapts to any environment and bites other mosquitoes, making it difficult to control,” said Zahiri. “Reproduction is another challenge because they prefer to lay their eggs in small containers, making it difficult to find all breeding sources.”

Aedes aegypti mosquitoes are about 6 mm long and will be identified by the black and white stripes on their bodies and legs. Their eggs are tiny and may seem like grains of dirt to the naked eye. These mosquitoes prefer to put their eggs above the water line in small, artificial water sources similar to buckets, animal bowls, fountains and water baths, flower pots and saucers, and old tires.

County officials said they don't know the way the mosquitoes got to East San Jose. They suspected the insect's eggs can have been unknowingly transported to the world — which is feasible for the reason that eggs can survive without water for a minimum of a 12 months.

The Aedes aegypti mosquito species is dangerously persistent and tends to be energetic throughout the day and bite multiple times, officials said. They only move a couple of block from where they breed, making it imperative for people to eliminate standing water where the mosquitoes could potentially breed and spread.

County officials really helpful cleansing and scrubbing birdbaths, pet bowls and other containers to remove any eggs that could be present, and urged residents to rigorously screen rain barrels, cisterns and irrigation canals to stop mosquitoes from entering.

County officials also really helpful that individuals protect themselves from mosquito bites by applying insect repellent with EPA-registered ingredients similar to DEET, picaridin, IR3535 or lemon eucalyptus oil, following label directions. They also really helpful that individuals wear long-sleeved shirts, pants, socks and shoes when mosquitoes are most energetic and be sure screens on windows and doors are in good condition.