Outmaneuvering Mosquitos

Mosquitos can be a nuisance in the hot summer months.

As the temperatures start to increase so do the ads for mosquito-control companies that offer to blanket spray residential landscapes.  While many of these businesses claim that their treatments only kill mosquitos and other pests, in reality the broad-spectrum insecticides they use kill many other species.

Broad-spectrum insecticides are indiscriminate, and along with killing mosquitos, they also kill pollinators and other beneficial insects such as bees, butterflies, moths, caterpillars, dragonflies, damselflies, and lady beetles.  The damage continues further up the food chain, when birds die as their insect food disappears and aquatic animals such as fish die when these chemicals wash off our landscapes and flow into nearby creeks, ponds, rivers, and lakes. Even spraying with essential oils such as peppermint, rosemary, and lemongrass is discouraged, as these can also kill beneficial insects.

Keeping mosquitos at bay can be vital, with many mosquito-borne tropical diseases such as West Nile, Zika, and Dengue fever spreading in range.  However, there are other natural, safer alternatives to using broad-spectrum insecticides.  It starts with understanding that mosquitoes can breed in less than one inch of water, and that the most effective way to reduce their numbers is to target the larvae, not spray adults.  

Moving water discourages female mosquitoes from laying eggs.

Begin by removing any standing water in gutters, bird baths, flower pot saucers, children’s pools, pet bowls, watering cans, and anything else that can hold water. Female mosquitoes avoid laying eggs in moving water, so consider adding a small pump or fountain to a water feature. For standing water that cannot be drained, use a mosquito dunk that contains the natural bacterium Bti (Bacillus thuringiensis israelensis) that kills mosquito larvae as they hatch, and consider adding native mosquitofish (Gambusia species) if the water feature is permanent.  Mosquitos are weak flyers, so even setting up fans reduces their ability to find an individual.

Black-chinned Hummingbirds get protein from eating insects like mosquitoes.

.

Neon Skimmer dragonflies love to prey on mosquitoes.

Most surprising to many, those who garden for wildlife using native plants have fewer mosquito problems than those with non-native turf lawns.  Native plants attract natural mosquito predators such as birds (warblers, wrens, woodpeckers, hummingbirds), dragonflies, damselflies, frogs, turtles, and bats.  Hummingbirds consume hundreds of insects daily in addition to drinking nectar, dragonflies and turtles eat mosquito larvae before they can hatch, frogs specialized sticky tongues nab all kinds of insects, and bats consume millions of insects on the wing.

The sticky tongues of frogs like this Leopard Frog can catch adult mosquitoes.

Red-eared Slider turtles eat mosquito larvae before they hatch.

It is important to note that even if you have a native landscape and don’t spray for mosquitos but your neighbors do, you will still lose pollinators and other beneficial insects.  Recent studies have shown that nearly 3 billion birds have disappeared from North America since 1970 due to loss of their insect prey, and many insect species are rapidly declining or vanishing altogether. 

Make your voice heard by spreading the message that insecticides are significant contributor to wildlife decline, and how we outmaneuver mosquitos in our landscapes truly matters to us all.

Night Bloomers

Berlandier's Trumpets

Many night blooming flowers have white or light-colored blossoms, a strong fragrance (although not always to human noses), and open by night and close by day.  These flowers are extremely important nectar sources for pollinators, and they are attracted to these flowers’ nectar mainly by scent.  Two of our best night blooming native plants are Berlandier’s Trumpets (Acleisanthes obtusa) and Jimsonweed (Datura wrightii).

Closeup of Berlandier's Trumpets

Also known as Vine Four O’Clock, Berlandier’s Trumpets is an upright perennial herb or climbing vine up to 6 feet long, easily controlled but often clambering over shrubs and small trees if left unchecked.  Its opposite, bright green leaves are triangular shaped, about 1.5 inches long, with slightly wavy edges.  But it is its white to light pink trumpet-shaped flowers, about 2 inches long, that bloom from April to December, producing a fragrant scent when open at night.  Berlandier’s Trumpet does well in full sun to part shade, is drought tolerant, and easy to grow and maintain.

Jimsonweed

Jimsonweed is a 3 to 6 foot tall stoutly branched herb, with alternate, coarse, large gray-green leaves that are broad at the base and pointed at the tip.  While its foliage is often described as rank-smelling, its flowers are sweetly fragrant white trumpets, up to 8 inches long, sometimes tinged with purple at the edges.  It blooms from May to November, and its flowers open in evening and close during the heat of the day.  

Jimsonweed Bloom

The fruit of this plant is a very distinctive spiny, globular capsule up to 1.5 inches in diameter, which opens fully when ripe.  Jimsonweed has several other common names such as Sacred Thorn-apple, Angel Trumpet, Devil’s Trumpet, and Sacred Datura. Some of these names refer to its use as a hallucinogen in Native American ceremonies, but it is important to note that all parts of this plant are toxic to humans.

Jimsonweed Fruit

Both of these native night blooming species attract several species of Sphinx moths (sometimes known as hawkmoths or hummingbird moths) as well as other pollinating insects such as long-tongued bees, butterflies, and hummingbirds.  But it is the Jimsonweed that has mastered the art of mutualism, with its partner the Carolina Sphinx.  

Carolina Sphinx

While it is common for this plant to benefit from its relationship with the Carolina Sphinx (Manduca sexta) in the form of pollination, in turn it provides nectar for the adult moth and is the host plant for the moth’s caterpillars.  These large caterpillars (known to gardeners as ‘tomato hornworms’), consume many or all of the Jimsonweed’s leaves. But the plant is prepared for the attack, storing resources in its massive root enabling it to produce more leaves for the next generation of caterpillars.  In effect, Jimsonweed grows its own pollinators to ensure its reproductive success!