All posts by sgn32

Uncategorized

Pest Watch: Mosquitoes in our Ecosystem

August 25, 2021 sgn32

By Cecille Jones, Monroe Master Gardener Volunteer

This article appeared in the August 2021 Issue of Gardening in Orange County.

Did you know one of the smallest insects in the world also happens to be the deadliest to humans? Yup, those pesky mosquitoes renowned for ruining many an outdoor evening event kill more humans every year than sharks, snakes, lions, crocodiles, and hippos combined. Of course they don’t do it alone; mosquitoes do not actually cause diseases themselves but act as vectors (carriers) for deadly diseases such as malaria, encephalitis, dengue fever, yellow fever, West Nile virus and Zika, to name a few. To transmit these diseases, mosquitoes first need to feed on the blood of a human or other animal that is already infected by the disease. Afterwards when they bite a healthy human, they pass on the disease.

Close-up of a blood filled mosquito — Female Mosquito

There are as many as 3,500 species of mosquitoes and they live on every continent except Antarctica. Not all mosquitoes bite, some adult mosquitoes feed exclusively flower nectar. And for the mosquitoes that do bite, less than one hundred species are carriers of horrible diseases. And it is only the female mosquitoes that take a blood meal from hosts like us. And they only do it, because they need the protein from our blood to produce their eggs.

Larvae of Culex Mosquitoes. As seen on the picture, larvae make dense groups in standing water. A shift in the feeding behavior of those mosquitoes helps explain the rising incidence of West Nile virus in North America. It appears that the darker structure at the top center of the image is one pupa. — Mosquito larvae (Culex sp.)

So, what are mosquitoes good for, you ask? Mosquito larvae are an integral part of the aquatic ecosystems in which they live. Mosquito larvae that live in wetlands consume a lot of organic matter. By straining organic particles through their system and converting into their own tissue matter they help recycle nutrients back into the ecosystem. Mosquito larvae serve as an important food source for other aquatic animals such as dragonfly larva and fish. From the human point of view, mosquitoes seem to exist to annoy us or make us sick, but from the point of view of spiders, birds, bats, reptiles, amphibians, fish, and other animals that rely on them as a source of food, mosquitoes are important for survival. For example, in the Arctic tundra, birds rely on the swarms of mosquitoes to stay alive.

A mosquito feeding on the nectar of flower with petals and a brown center Mosquitoes are beneficial to plants as well. Many adult mosquitoes depend on plant nectar for their energy, and while retrieving the nectar, they also pollinate plants. And as we know that pollination is key to plant reproduction, mosquitoes play an important role in helping plants survive so they can provide food and shelter for other organisms.

The reality is that not enough is known about all the interspecies interactions of mosquitoes to get rid of them without doing harm to other species in our ecosystems. In the meantime, scientists are studying mosquito saliva in hopes of finding properties that can lead to the development of anti-clotting drugs that can be used to treat cardiovascular disease. Until that day arrives, we may not have a conclusive answer to the question: What are mosquitoes good for?

Learn more about mosquitoes:

VIDEO: Mosquitoes in Your Back Yard – NYS Integrated Pest Management, Cornell University

Mosquitoes – NYS Integrated Pest Management, Cornell University

Mosquitoes – Medical Entomology, Purdue University

Meet the Mosquito With a Big Appetite⁠—for Other Mosquitoes – Entomology Today

Out in the Garden

Strategies for Removing Invasive Species

August 18, 2021 sgn32

By Linda Gayton, Highland Mills Master Gardener Volunteer

This article appeared in the August 2021 Issue of Gardening in Orange County.

When it comes to invasive species, patience and persistence are key. This is a marathon not a sprint. Eradicating invasive species takes the determination of the tortoise, not the hare. We need to exercise a consistently forward, strategic plan to manage our alien invaders. A fast sprint to the win is not usually possible.

invasive species – a non-native species to the ecosystem that they occupy, AND who’s existence causes harm to the economy, the environment, or human health.

Invasive plants grow quickly, and spread to the point of disrupting communities and ecosystems. For the most part, these invaders are not affected by native pests and diseases. The only predator they will encounter in our landscape is you.

Why should we care about invasive plant species?

Invasive plants degrade native habitat. They are poor food producers for our native wildlife. They clog waterways, destroys native habitats, ruins views, and causes wildfires. Millions of dollars a year are spent on control methods.

What are the benefits of managing invasive species?

Managing invasive species benefits wildlife, the environment, and ourselves. Our goal is to create resilience in our ecosystem. By restoring areas dominated by invasive species and helping native plant communities to thrive we can help allow biodiversity to persist and help keep natural areas intact.help allow biodiversity to persist and help keep natural areas intact.

Integrated Pest Management

To begin to eradicate invasive species, we must first develop an Integrated Pest Management (IPM) plan. IPM is a process we use to solve pest problems while minimizing risk to people, wildlife, and the environment.

There are 6 steps to an IPM strategy:

1. Sample for Pests (Inspect and Monitor): Is there a real problem?
2. Properly identify pests: Is it really the pest you think it is?
3. Learn the pest biology: Will it be a long-tern problem, or will it be gone next week?
4. Determine an action threshold: Do you need to act?
5. Choose Tactics: What’s the best treatment?
6. Evaluate: How did it work?

When it comes to control tactics in IPM, we start with the least toxic when available and move up the pyramid to the most toxic (conventional pesticides) as needed.

Here are some IPM Strategies to implement when dealing with what I consider three of our top plant invaders:

- Common Reed / Phragmites (Phragmites australis)
- Japanese Knotweed (Fallopia japonica)
- Multiflora Rose (Rosa multiflora)

For each of these formidable opponent, we head right to the mechanical/physical control methods followed by strategic application of chemical herbicides.

Sketch from an old book of a man with a backpack sprayer spray a tree, under sketch are the words Fig. 97 La Torpille Duster. Some of the following strategies include herbicide recommendations. Every effort has been made to provide correct, complete, and up-to-date herbicide recommendations. Nevertheless, changes in herbicide regulations occur constantly and human errors are still possible. These recommendations are not a substitute for herbicide labeling. Please read the label before applying any herbicide. The label is the law!

Xylem (blue lines) carries water from the roots upwards phloem (orange line) carries products of photosynthesis from the place of their origin (source) to organs where they are needed (roots, storage organs, flowers, fruits – sink); note that e.g. the storage organs may be source and leaves may be sink at the beginning of the growing season If you decide to use an herbicide to combat these invaders, timing is key. When applied to a plant, the herbicide glyphosate, one of the most widely used weed killers, will be translocated in the plant’s phloem, which the plant uses to transport sugars and other metabolic products. But the herbicide will only be transported in the direction the plant is moving sugars. For the majority of the season plants are using sugars that they had stored in the rhizomes to grow, meaning that sugars are moving upwards in the plant’s phloem. Only once a plant starts to flower does it begin to store sugars back down in the rhizomes, meaning that sugars are moving downward in the plant and when applied glyphosate will reach the rhizomes. Both Phragmites and Japanese knotweed have extensive rhizomes

Carefully disposing of plant material from invasive plants is extremely important as many invasive species can grow from small fragments. Two common practices are burning plant material (according to state and local laws) and putting it in black garbage bags and sending it to the landfill. To reduce the volume before shipping it off to the landfill, you can leave it on an extremely hot surface such as an asphalt driveway prior to being discarded. You should not try and compost this material as it will most likely resprout and cause more problems.

Common Reed / Phragmites

Common reed - stand of tall grass with seed head on top Phragmites, also known as common reed, is a perennial grass that can grow over 15 feet tall. It is commonly found in marsh and wetland areas where it forms dense stands that crowd out native vegetation. These monoculture that do not support the diversity needed for a thriving ecosystem

Phragmites spreads by both rhizome and wind pollinated seed. It has very deep roots and thrives in moist areas and aquatic environments. It also conducts chemical warfare against other plants by secreting allelochemicals to suppress their growth.

For this formidable opponent, we head right to the mechanical / physical control methods followed by strategic application of chemical herbicides.

Method A: Clip and Drip

After the plant has flowered, clip and remove stem, then immediately apply the herbicide glyphosate, to the hollow stems with a drip bottle. Stems can be bundled before they are clipped to make it easier to drip herbicide on hundreds of stems simultaneously. This method is extraordinarily labor intensive but can work wonderfully without the loss of native plants. Remember to dispose of any cut material properly.

Method B: Cut and Spray

After the plant has flowered, cut and remove stem followed by targeted spraying of an appropriate herbicide via backpack mounted sprayers or mist blowers. Remember to dispose of any cut material properly.

Method C: Burn It

Conduct a controlled burn following state and local laws as well as safety guidelines. This will kill stems and seeds. If regrowth occurs use chemical methods.

Method D: Drown It

Drown it. Cut stems under 6” of water. Dispose of cut material properly. Phragmites will drown in 1 year by early fall if water level is maintained.

For each of these methods, it is important to reevaluate yearly and determine what if any further eradication is necessary. Once removing a stand of phragmites make sure you remove the layer of dead shoots, stems, and roots on top of the soil surface before a restoration planting of native plants.

Japanese Knotweed

Japanese knotweed in full bloom Japanese knotweed is an herbaceous perennial that creates dense thickets that crowd and shade out native vegetation. In the United States rhizomes can reach 30-75 feet in length and are the chief cause of spread. Fragment of stem and rhizome can regenerate new plants. In big storm events pieces of the plant are broken off and transported to new areas, where they can establish new colonies. Finding small plant fragments digging them out and disposing of them properly can go a long way in saving resources, time, and the damage of future infestations.

Along waterways Japanese knotweed replaces riparian vegetation reducing diversity and altering the aquatic ecosystems. The loss of tree and shrub canopy can cause an increase in water temperature which in turn affects water chemistry and fish habitat. The loss of leaf litter and woody debris results in a loss of shelter for fish and invertebrates. The inability of ground covers and mosses to grow beneath the dense canopy of knotweed results in bare soils leaving banks susceptible to erosion resulting in siltation in stream beds, which again alters fish habitat.

We will once again skip up the pyramid and head to our mechanical/physical management tools in order to begin controlling Japanese knotweed.

Method A: Dig, Dig, Dig

Cut the knotweed stalks, digging out the root crowns and as much of the rhizome network as possible. This is very labor intensive and may take several years to gain control of a stand of Japanese knotweed.

Method B: Cut, Dig, Cover

Cut the knotweed stalks, digging out the root crowns and as much of the rhizome network as possible. Then cover the ground with thick black landscape plastic to block sunlight and thereby destroy any remaining rhizomes. Leave covered for at least one year. Experimental plots which were left covered for three years, showed less regrowth of knotweed.

Method C: Cut, Cut, Cut

Cut down knotweed plants 2 or 3 times each growing season. Dispose of properly. Several years of successive cutting will weaken the knotweed’s rhizomes, so they can be pulled out with relative ease.

Method D: Cut and Spray

Biological Control

The Knotweed Psyllid (Aphalara itadori) was released on June 10th, 2020, in New York’s Tioga and Broome counties. Research and monitoring are ongoing.

For each of these methods, it is important to reevaluate yearly and determine what if any further eradication is necessary. Once control has begun make sure to implement a restoration planting of native plants.

Multiflora Rose

A large thicket of multifloral rose in bloom on the edge of a wooded area Multifloral Rose is an herbaceous shrub in the rose family (Rosaceae). It has canes or stems) have numerous thorns and can grow up to 15 feet in length and usually arc toward the ground and takes root, a process called layering. This creates dense thickets 6-10 feet tall. After establishment, individuals can increase their size by 1-2 feet a week during midsummer. Multifloral rose has clusters of showy, fragrant white flowers in late May or June. It spreads through seed, root sprouting, and layering. The fruit, known as rose hips, are eaten and dispersed by our feathered friends, and can persist and remain viable in the soil for up to 20 years.

Method A: Dig, Dig, Dig

Remove isolated individuals before they multiply. Small populations of young plants are not difficult to pull taking care to use protection against thorns. Be sure to pull the entire root system to prevent re-sprouting.

Method B: Mow, Mow, Mow

Repeated cutting or mowing at the rate of three to six times per growing season, for two to four years, has been shown to be effective in achieving high mortality.

Method C: Cut and Spray

Mow or cut large infestations to prep for herbicide application After mowing, wait for knee level regrowth before treating with herbicide. While foliar sprays can be done anytime during the growing season, all these chemicals will also harm non-target herbaceous plants and trees if applied to their leaves. Care needs be taken to prevent damage to non-target plants.

As previously stated, patience and persistence are necessary when attempting to eradicate an invasive species. In order to sustain myself through what seems like a never-ending task, I maintain the attitude that I am working with nature on a productive journey. I find also that monitoring progress and achieving even minimal success is very encouraging. When we keep in mind all the positive effects that our efforts are having on the wildlife, our ecosystem, and ourselves, the reward is great.

It is my hope that I have shared some of the tools to help you take on one or more of our invaders.

Stop the Silent Invasion!

Please spread the word, not the weeds !

Resources

General

Managing Invasive Plants: Methods of Control – University of New Hampshire Extension

Mistaken Identity? Invasive Plants and their Native Look-alikes – Delaware Department of Agriculture

New York State Invasive Species – New York Invasive Species Information – Cornell University

Common Reed / Phragmites

Common Reed – New York Invasive Species Information – Cornell Cooperative Extension

Successfully Managing Phragmites – Ecological Landscape Alliance

Japanese Knotweed

Homeowner’s Guide to Japanese Knotweed Control – Wisconsin Department of Natural Resources

Japanese Knotweed – New York Invasive Species Information – Cornell Cooperative Extension

Japanese Knotweed – University of Wisconsin Extension

Managing Japanese Knotweed: Two Small-Scale Strategies – Ecological Landscape Alliance

Multifloral Rose

Multifloral Rose – New York Invasive Species Information- Cornell Cooperative Extension

Multifloral Rose – Penn State Extension

Plant of the Month

Plant of the Month: Goldenrod

August 16, 2021 sgn32

By Linda Gayton, Highland Mills Master Gardener Volunteer

This article appeared in the August 2021 Issue of Gardening in Orange County.

Goldrod being visited by afly — Canada Goldrod (Solidago canadensis) being visited by a fly

A bee visiting the yellow flowers of an Alpine Goldenrod plant — Tall Goldenrod (Solidago altissima)

Close-up of small yellow flowers of alpine glodenrod. — Alpine Goldenrod (Solidago leiocarpa)

Goldenrods are members of the aster family (Asteraceae) and most are of the genus Solidago. There are over two dozen species of goldenrod native to New York State varying in height from the 14 inch tall Alpine Goldenrod (Solidago leiocarpa) to the 4-6 foot Tall Goldenrod (Solidago altissima). Most of New York’s goldenrods are late bloomers putting out flowers in late summer and fall. As one of the few groups of wildflowers in peak bloom at this time, many insects depend on these plants for food. Goldenrods also provide food for birds and small mammals through their prolific seed production. On sunny days goldenrod patches are a good place to watch for butterflies including painted ladies, monarchs, and viceroys. In addition to butterflies, many species of bees, wasps, and beetles can also be seen collecting pollen and nectar from the hundreds of tiny flowers that make up a goldenrod’s inflorescence or flower head.

Brifht yellow flowers on a tall goldenrod — Seaside Goldenrod (Solidago sempervirens)

This hardy perennial thrives in a variety of habitats including roadsides, fields, wet and dry prairies, sandy banks, swampy bogs, and forest openings. Some species will even thrive in sand dunes by the ocean or on rocky summits. On the east seaboard, Seaside Goldenrod (Solidago sempervirens) grows in abundance stabilizing sand dunes and providing a vast food supply for monarch butterflies on their long migration south.

No matter your garden aesthetic, there is goldenrod for you. Gardeners who prefer tidy borders can choose clump forming varieties, whereas gardeners desiring a more naturalistic look may be able to accommodate the self-seeding or rhizomatous types. Most goldenrods are very hardy and vigorous with few diseases or insect problems. The spiky, fleecy, or sometimes flat-topped yellow flowers are versatile accents to the strong purples and pinks of aster, sedum, and joe-pye weed. They also complement dainty flowers of native grasses and lobelias.

A large group of flowering ragweed — Common Rageweed (Ambrosia artemisiifolia) in bloom

For gardeners concerned about goldenrod’s alleged allergy inducing pollen, please note that goldenrod produces a sticky pollen meant to attract and adhere to insect pollinators not allergy inducing wind-borne pollen. One of the main culprits of late summer /early fall allergizes is ragweed, a common garden weed that blooms at the same time and often alongside goldenrod. Ragweed goes unnoticed in the landscape because of its drab green flowers, which generates an unusual amount of wind-borne pollen much to the chagrin of allergy sufferers. Goldenrod pollen will only affect an allergy sufferer if they stick their nose into a flower and take a big sniff.

Large golden candle shapped infloresence of showy goldenrod — Showy Goldenrod (Solidago speciosa)

Understanding this misconception between ragweed and goldenrod is important, as the goldenrods comprise a diverse genus with tremendous horticultural potential. Goldenrod is one of the absolute best native perennials for biodiversity. Add it to your pollinator gardens and let people know it is a friend, not a foe.

August, Gardener's Checklist

Gardener’s Checklist

August 11, 2021 sgn32

August 2021

Garden Maintenance

Autumn Crocus (Colchicum spp.)

Install pollinator hotels for tunnel nesting bees.

For some small color, plant some autumn crocus.

Deadhead annuals and perennials regularly too encourage new blooms.

When it comes to lawn care—do less: mow less, limit watering, live with some weeds,

Consider adding some herbs to you perennial flower garden.
Invasive Japanese Knotweed

Webinar: Gardening with Herbs – Cornell Cooperative Extension Chemung County

Remove invasive species from your yard.

Don’t be too tidy—leave some flower heads and stalks for birds and other over-wintering pollinators.

Pest Watch

A silken fall webworm nest at the end of a branch full of caterpillars. — Fall Webworm Nest

Remove fall webworm nests.

Keep pests out of your home this fall!

Webinar: Keeping Pests Out of Your Home this Fall: From Stink Bugs to Mice – NYS IPM

Scout your lawn for grubs⁠—before you treat!!

VIDEO: Using IPM to Assess Your Lawn for White Grubs – NYS IPM

Dump out any standing water from containers in your yard to prevent mosquito breeding.

A very holey head of cabbage a result of feeding by the imported cabbageworm — Imported cabbageworm damage on cabbage.

How to Manage Mosquitoes in the Landscape – New York State Integrated Pest Management

Scout often for pest in your vegetable garden.

What Kind of Insect is Destroying my Plants?– Gardening in Orange County New York Blog

Vegetable Gardening

Rejuvenate your soil by planting a fall cover crop such as barley or clover.

Light purple clover flower against a background of green leaves — Clover makes a great fall cover crop.

Webinar: Cover Crops for the Home Garden – Cornell Cooperative Extension Tompkins County

Conserve water by knowing when and how to water your garden.

Seed and transplant crops for an autumn harvest.

Continue to remove weeds, as they compete with your garden plants for water, sunlight, and space.

Bottom of basil eaf covered with downy mildew spores — Basil Downy Mildew

Monitor you basil plants for basil downy mildew.

Monitor you cucurbit plants for cucurbit downy mildew.

Preserve your bounty.

Webinars: Food Preservation – Cornell Cooperative Extension Tompkins County

Happy Gardening!

J. Scharfenberger — Black Swallowtail on Lupine ‘Tutti Fruitti’

Vegetable Gardening

Seven Crops to Plant in August for a Fall Harvest

August 10, 2021 sgn32

By Cecille Jones, Monroe Master Gardener Volunteer

This article appeared in the August 2021 Issue of Gardening in Orange County.

If you have been enjoying your summer vegetable harvest, there is no reason why you can’t extend your growing season through the fall and winter.

Those of us who live in Orange County, NY, are in planting USDA Hardiness Zone 6A/6B and can expect the first frost to arrive on or around October 15. Since planting for a good fall harvest starts six to eight weeks before the first anticipated frost date, the dog days of August are a good time to start.

Here are seven crops good for Zones 5 – 7 that you can plant this month for nutritious edibles on your dinner table.

Brassica or Cole Crops

Head of broccoli growing on a broccoli plant — Broccoli

What could be more delicious than garden fresh broccoli, cabbage, cauliflower and Brussels sprouts? This family of plants are perfect crops to harvest come fall. Plant them as seedlings or starters from your local nursery, not as seeds. Put the starters in the ground six weeks before the first frost and plan on protecting them late in the season with a fabric row cover or a hoop house. If you want to plant from seeds, June of next year is the time to start.

Kale

All types of kale also belong to the Brassica family, but kale can be planted by seed or seedling all through August. If you are short on time by a couple of weeks, you can always harvest baby kale, something the supermarket sells at a premium. As this plant matures, frost and even freezing temperatures sweeten them. To overwinter kale, protect them with a piece of heavy row cover.

Lettuce

Summer heat can burn lettuce leaf tips and cause it to get bitter, but not so for lettuce planted through August and harvested in the fall and early winter. Despite its appearance, lettuce leaves are hardy and can easily tolerate cold night temperatures and moderate frost. You can plant seeds 8 weeks before the first frost. If you want to harvest baby greens, you can plant as late as two weeks before Jack Frost makes his entrance. To get a good start on early spring lettuce next year, you can overwinter lettuce in a cold frame.

Asian Greens

Also, part of the Brassica family, Chinese greens like pak choi and tatsoi are quite hardy and grow well in the fall. You can plant these from seed eight weeks before October 15. If you want an earlier harvest, start them indoors and then tuck them in your garden as spots start to clear out in August.

Spinach

For a long harvest, plant the amazing spinach. If you start in August, you will be enjoying this vegetable by mid-October. Use protection from a hoop house or cold frame and you can continue harvesting small amounts all winter long. When spring arrives, this plant will take off again and yield a great harvest until May.

Beets

You cannot go wrong with planting beets. To harvest the root crop, you need to plant eight weeks before the first frost, but do not let the calendar stop you. Anything planted after six weeks before the frost will yield tasty tops, which you can add to your fall salads. Sadly, beets are not hardy enough to survive the winter.

Carrots

Carrots make a great fall and winter treat. With colder temperatures, the starches turn to sugars, making carrots sweet and delicious. Give your carrot seeds a good, healthy start by watering the seedbed once or even twice daily. When the weather starts to get colder in December, use a hoop house, cold frame or straw cover. You might also want to pick a variety that has a short maturity date so they can get ready by winter.

There are many other crops you can plant in August. Think arugula, radish, and leeks. Whatever you decide to plant, here is to a bountiful fall harvest and bon appetit.

(Special thanks to Master Gardener Sabrina Conti for sharing information on fall harvesting.)

Uncategorized

Tree of the Month: Black Willow

July 30, 2021 sgn32

By Cecille Jones, Monroe Master Gardener Volunteer

This article appeared in the July 2021 Issue of Gardening in Orange County.

Willows include more than 400 trees and shrubs from the Salix genus. New York boasts more than 15 native willow species. Whether it’s a balsam willow, bearberry willow, heart-shaped willow, pussy willow, peach-leaf willow, or sageleaf willow, they all have similar characteristics. All are moisture-loving plants native to temperate and cold regions in the Northern Hemisphere. They range in size from low ground-hugging shrubs to giant trees towering up to 90 feet.

Black willows along the water's edge in a wetland area — Black willows line a stream bank

Regardless of stature, willows play an important role in maintaining the health and vigor of many wetland environments. First and foremost, willows reduce erosion. They have large and expansive root systems that grip sediment and keep shorelines in place. As a result, they are used in many habitat-restoration projects.

A secondary benefit, willows grow fast and propagate easily. Moreover, they are known to cleanse the environment of toxins by sequestering high levels of heavy metals such as cadmium.

With their densely branched and foliated leaves, willows help to reduce the water temperature in wetlands adjacent to rivers and streams, helping protect cold water fish such as trout and perch.

Bumble bee collecting nectar from a willow catkin — Bumblebee visiting a willow catkin

Finally, willows produce beautiful catkins in the spring, providing a food source for pollinating insects. Caterpillars feast on their leaves, and birds use their tightly clustered branches to nest and hide from predators.

In landscaping, willows can be used to create living fences, or even sculptures. However, be cautious about planting willows near sewer lines or water pipes. Because willows seek out underground water, their roots will penetrate a water main or sewer line, resulting in thousands of dollars in repairs.

For people looking to help restore wetland habitat to its former glory, willows make the perfect choice. A good example of one such willow is the black willow (Salix nigra). This tree is the largest and most important among the willows. They prefer cool climates and thrive in plant hardiness zones 2 through 8. They hold the distinction of having one of the most extensive ranges across the United States.

Large black willow tree on the edge of a field — Black willow (Salix nigra)

The black willow is considered a small to medium-sized tree, growing between 10–60 feet. Leaf blades are up to 5 inches long, narrow and tapering to an elongated tip, with margins finely serrated. They bloom from April to May and have bright yellow-green twigs that bear yellow-green catkins. They bear inconspicuous clusters, with male and female flowers on separate trees.

Balck willow tree in bloom — Black willow in early spring

Black willows often have several trunks up to 14 inches in diameter growing out of one root. These trees are topped by a broad, irregular crown that provides ample shade in summer. Usually found along stream banks, swamps, farm ponds and pasture sloughs, black willows love moisture but will also tolerate drier soil, although that reduces vigor.

One of the lightest of eastern hardwoods, the black willow is paradoxical. It is structurally weak, but when nails are driven into it, black willow wood does not split. Being light and flexible, black willow wood was once used to make artificial limbs. Today, it is often used to make shipping boxes and toys.

Uncategorized

Pest Watch: Basil Downy Mildew

July 28, 2021 sgn32

This article appeared in the July 2021 Issue of Gardening in Orange County.

Basil downy mildew has been a persistent deadly disease of greenhouse and garden basil crops in the US for over 10 years. It is caused by the pathogen Peronospora belbaharii. This fungus-like oomycete can infect the plant during its whole lifecycle from seed to full maturity. Pesto lovers beware since sweet basil (Ocimum basilicum) is the most susceptible.

Signs and Symptoms

Slight yellowing of basil leaf — Chlorosis of a basil leaf

Usually the first symptom is a non-specific chlorosis or yellowing of the top portion of the lower leaves of the basil plant that then travels up the plant. The discoloration is contained within the borders of the major veins of the leaf. The affected leaves will eventually wilt or curl, die and turn brown. A distinguishing feature of basil downy mildew is the fluffy purplish gray spores that grow on the undersides of the leaves. Unfortunately, infected plants and seeds may not show any signs or symptoms especially if in cool, dry conditions.

Transmission

Peronospora belbaharii is primarily spread via wind-borne spores called sporangia. Contaminated seeds, other basil plants, garden tools and gloves are other forms of transmission. The spores thrive in warm, humid and wet conditions but can still infect plants and reproduce in temperatures as low as 59° F.

Basil downy mildew does NOT overwinter here in New York. It can NOT survive in the soil or on dead plant tissue (like many pathogens). Each year spores are carried up from the southern United States by the wind.

Management

Basil downy mildew is difficult to treat once the disease has been established. High temperature steam treatments have shown promise in eradicating the pathogen on basil seeds. There has also been some success in developing disease resistant cultivars for less susceptible varieties of basil such as red leaf, lemon, and spicy basil, but developing disease resistant cultivars of sweet basil has proven more challenging. According to research at Cornell University evaluations the sweet basil cultivars ‘Eleonora’,, ‘Prospera’ and ‘Pesto Besto’ may be some good options.

Since basil downy mildew is an oomyete and not a true fungus, fungicides have limited value and are not recommended for the home gardener. Because basil downy mildew does NOT overwinter in New York, removing crop debris at the end of the season and crop rotation are not helpful for management of basil downy mildew.

Monitoring and cultural practices have been most successful especially in the home garden and greenhouse settings. Monitoring all seedlings and plants for yellowing leaves and gray downy growth is imperative. Once you determine your plant is infected, immediately harvest the unaffected leaves for culinary purposes, and then remove the plant and dispose of it in the garbage.

Map of northeastern United States showing new confirmed cases (in past 14 days) of basil downy mildew in eastern Pennsylvania, eastern Massachusetts, and south eastern Rhode Island, and older confirmed cases (over 14 days ago) in Delaware, southern New Jersey, Long Island (NY), and western Massachusetts — Basil Downy Mildew Map (July 27, 2021)

The annual spread of basil downy mildew is monitored and confirmed cases are tracked. To have a better idea as to when your plants are likely to become infected, you can follow the spread of basil downy mildew on the ‘Basil – Ag Pest Monitor‘ website and sign-up for alerts.

Reducing leaf wetness can be helpful in preventing infection. Always water basil plants at the base either by hand or using a drip irrigation system. Plant basil in full sun and maximize your spacing between plants to provide good air movement. These practices allow the leaves to dry quickly after rain or dew. If you are growing basil indoors or in a greenhouse, an effective way to increase air circulation and reduce leaf wetness is by directing a fan towards the plants.

If you accidentally eat a piece of basil with downy mildew, don’t worry. Pathogens that cause diseases in plants are different than the pathogens that cause disease in humans. It’s not poisonous to humans and should not cause you any symptoms.