Insects and Pests


praying mantid 2

Praying mantids have hatched and are busy staking their claim in all areas of the garden looking for any insect to eat. They are fun to watch and photograph. So glad I noticed their egg masses and relocated them when cutting back the garden last fall.

clove current berries

The clove currant is producing berries, first green then ripening to black. The birds are eating them faster than I can take a photo them almost. Good plant for wildlife, and a hand-me-down plant from my husband’s grandmother’s home. The Latin name is Ribes odoratum for those doing a search to find one.

swallowtail butterfly

This swallowtail butterfly was very busy feeding on the nectar of the very floriferous bottlebrush buckeye blooming on campus. Bottlebrush buckeye, Aesculus parviflora, is a fabulous, large shrub which sends up panicles of white flowers with red anthers and pinkish filaments.

spinach bolting 2

The summer’s heat is causing the cool weather crops of the spring to bolt and go to seed. Once this happens, the leaves become bitter and plants should be pulled and composted. Planting fall crops of carrots, beets, peas, kale or beans make good use of then now available space in the garden.

Robber fly

This robber fly was resting in the garden, probably waiting for an easy insect meal. They are predatory on all types of insects and considered a beneficial insect.

cross striped caterpillar on cale

If your kale or other cole crops are being eaten and showing a lacy appearance of holy leaves, look for the cross-striped cabbage worm. One caterpillar can eat quite a lot. Bt is a good control measure when they are small, or insecticidal soap. Rotate where brassica plants are located next year, and grow under a row cover to keep the adult moth from laying her eggs on the leaves.

garlic

Garlic is ready to be harvested during July, once half of the leaves have turned brown. After carefully loosening the soil with a spade, pull the garlic bulbs by the stems and dry on an open rack in out of the sun and under cover for three weeks. A shed or garage are best for the drying. After they are dry, brush off the dirt, cut off the roots close to the bottom of the bulb, and cut back the stem end leaving about one inch. Store in the home in a dry, dark spot. Save the largest bulbs for planting next October through November.

gypsym moth females and egg masses

Gypsy moth adults are busy mating. Females do not fly, only able to crawl. The males are flitting around, flying to females to mate. Females will lay the buff colored egg masses which will last through the fall, winter and spring, to hatch next summer. Egg masses can be  crushed or scraped into a container of soapy water.

-Carol Quish

All photos are copyrighted by Carol Quish, UConn.

 

 

 

 

 

 

 

 

 

If you grow leafy greens in your garden, it’s likely that you grow spinach. It can be a little (or more) disappointing to pop out to the garden to harvest some only to find that some of the leaves have damage in the form of whitish winding or blotchy patterns as shown below.

 

These are the handiwork of the spinach (Pegomya hyoscyami) or beet (P. betae) leafminers. On spinach, it’s most likely the spinach leafminer but their biology and damage is pretty much the same. Beet leafminers prefer to lay their eggs on beets if they’re available. In my garden, both plants are present so I think I’ve got the spinach species because the beets are not affected.

This pest overwinters in the soil as a pupa right near the plants it developed on the previous season. In the spring from roughly late April through mid May, adult flies emerge, mate and lay eggs. This is the best time to apply an insecticide if you’re going to because you need to intercept the tiny maggots between the time they hatch and the time they burrow into the interior of the leaves. This is a very short window of time. Scout for the clusters of tiny white eggs (visible to the naked eye) on leaf undersides.

spinachLMeggs.JBoucher

Spinach leafminer eggs. Photo: J. Boucher, UConn

 

Alternatives to insecticides for the home garden include crushing the eggs, removing leaves with eggs or mines/larvae and disposing of them in sealed bags in the trash, and crop rotation combined with the use of floating row covers for the next crop. Another option for infested leaf disposal is to bury them deeply in your compost pile where they will not survive.

SpinachLMmaggot.JBoucher

Spinach leafminer maggot (larva). Photo by J. Boucher, UConn

It’s important to keep in mind that the life cycle of the leafminers is only 30-40 days long so there can be 3-4 generations per year and they can overlap. If you have damage in your spring crop and are planning on a midseason/fall crop, move the spinach, beets and chard to a different area and cover prior to adult emergence with floating row cover to exclude the adult flies. Adults are tiny, hairy gray flies about 5-7mm long.

Image result for spinach leafminer adults

Adult spinach leafminer (Whitney Cranshaw photo, Bugwood.org).

In beets, moderate damage will not affect the development of the root crop. This pest is most important in plants grown for edible greens. Having said that, severe damage in beet leaves can result in poor root development.

By Joan Allen

According to the language of flowers, the rose belongs to the month of June symbolizing love and passion, gratitude and appreciation. Well I am passionately in love with and greatly appreciate all of June’s flower blooms, including roses.

Rose, red climbing-1

Roses can be found in home gardens, public gardens and even commercial parking lot plantings, usually as tough shrub rose varieties needing little care. Hartford is the proud location of Elizabeth Park, the oldest municipal rose garden in the United States established in 1904. Within its boundaries are beds and arches filled with hundreds of rose plants loving tended by professionals and volunteers, all taking pride in creating a beautiful and scent filled space for all to enjoy. http://elizabethparkct.org/gardens-and-grounds.html

 

Check rose plants carefully as gypsy moth caterpillars are feeding on leaves currently. Hand pick off and kill the little buggers by squishing or dropping in a container of soapy water. Signs they were there and left are shown by them leaving their shed exoskeleton after they molt.

gypsy moth caterpillars and rose

Gypsy moth on rose leaf, C.QuishPhoto

gypsymoth molted exoskeleton

Gypsy moth caterpillar shed exoskeletons. A sign gypsy moths were here. CQuish photo

Not all roses are a considered a ‘bed of roses’ or a good thing. The multiflora rose, Rosa multiflora, is an invasive species of rose, overtaking and displacing native plants. It was introduced to the U.S. from Asia in 1866 for use as rootstock and later widely planted as hedgerows and living fences.  Due to its very thorny nature, animals did not attempt to cross. Multiflora roses can be identified by its fringed petioles which differ from most other rose species. When in mass  blossom, the make the June air incredibly sweet.

Rose, multiflower, C.Quish

Fringed petiole of multiflora rose, C.Quishphoto

A few other fabulous flowers caught my eye and camera lens this month so far. Lunchtime walk on the Storrs campus I found an unusual shrub in front the Castleman building. False indigo, Amorpha fruticosa, was sporting spires of purple and orange flowers similar to butterfly bush. I had never seen it before, and after researching its identity, I am glad I haven’t as the CT Invasive Plant Working Group has it listed as ‘Potentially Invasive’. It seems well behaved in the restricted spot surrounded by buildings and pavement, but pretty still the same.

False indigo bush cquish

False indigo, CQuish photo

The perennial Helen Elizabeth Oriental poppy is a lighter pink, eschewing the brazen orange color of traditional oriental poppies. Helen Elizabeth is softer on the eyes and blooms a little bit later than the orange one.

 

Annual poppies are just beginning to bloom in my garden. If you let them go to seed and collect the seed once the pods go brown, dry and rattle, you will have an incredible amount of seed to save, share or spread the beauty in other areas.

 

Foxgloves, Digitalis sp, are shooting up their towers of flowers in different colors. Some species are biennial and others are perennial. The spots on the throats of the flowers are believed to be nectar guides showing the bees and other pollinators the way in to find the location of the nectar.

Visit local, independent garden centers and nurseries for unusual plants not found in the big box stores or chain centers. I found the annual Popcorn Plant, Cassia didymobotrya, whose leaves smell like buttered popcorn when stroked, at Tri-County Greenhouse on Rt. 44 in Storrs Mansfield. A treasure trove of unknown annuals and surprising perennials, and large variety of tomatoes and vegetables were all over the sales yard. I especially love the philosophy of the place hiring very capable people with intellectual disabilities along with some great horticulturists.

June also brings disease and insects to the garden. A few of the things we are seeing from submissions for diagnosis to our office are shown below. Azalea galls were sent in from South Windsor and are being reported around the state. The fungal disease, Exobasidium vaccinii, develops from an overwintering infected plant part of azalea leaf, twig or flower, and malforms the plant tissue into a curled and thickened gall.  As the gall ages it turns white releasing more spores to infect fresh tissue. Control should be to hand cut off and destroy galls before they turn white.

Azalea gall, b.zilinski 2

Azalea gall, B.Zilinski photo

Another sample image sent in were sweet birch leaves with bright red growths called Velvet Galls. These red patches are soft felt-like growths made by the plant in response to  to wall off the damage by a tiny eriophyid mite feeding on the leaves. The red patch is called an erinea. Unsightly while still being pretty, the damage is considered only cosmetic and causes no lasting harm to the tree. Thanks to Jean Laughman for her photos.

velvet gall on birch 2 Jean Laughman photo

velvet gall on birch,Jean Laughman photo, 6-8-18

Another great photo was sent in by Shawn Lappen for insect identification. The Dusky Birch Sawflies were striking a classic pose while eating the heck out of the leaves of a birch tree. Sawflies are stingless wasps whose larvae are plant feeders. The larvae are not caterpillars as this insect is not in the butterfly and moth order of Lepidoptera. Feeding damage usually does not cause much damage to a tree in good health. If control is needed, insecticidal soap will suffocate the larvae when sprayed on them.

Dusky Birch Sawfly, from Shawn Lappen

Golden tortoise beetles are attacking morning glory and sweet potato plants. They look like a little drop of gold but their beauty belies their destructive nature. Hand picking and dropping into a container of soapy water will kill them quickly.

Golden Tortoise beetle

Be on the lookout for Luna moths during the month of June. It is one of the largest silk moths and is attracted to lights at night. After mating, the female will lay her eggs on one of the host plants for the caterpillars including white birch (Betula papyrifera), persimmon (Diospyros virginiana), sweet gum (Liquidambar styraciflua), hickories (Carya), walnuts (Juglans), and sumacs (Rhus). The photo below was sent in to us last June 4 by A. Saalfrank.

Luna moth A.Saalfrankphoto 6-4-2017

Leave the light on to attract Luna Moths

-Carol Quish

This is the time of year when summer-blooming bulbs appear in every garden shop, hardware store, or even grocery store. Like a kid in a candy store, I can look at them for ages, dreaming of the colors and shapes that could appear in my garden. Recently the image on a package of Asiatic lily bulbs jumped out at me.

Dark Lady blend 2

The mix of antique-looking purples, creams, and pinks would be a beautiful addition our garden bed where limelight hydrangeas, pale drift roses, and a Dogwood Cornus florida with its pale cream blossoms touched with pink.

Asiatic lilies, along with Easter lilies, are true lilies in the genus Lilium and Fritillaria, in the genus Fritillaria, are members of the family Liliaceae. The trumpet-shaped blooms of the Asiatic lily flower in early summer and may face upright atop stems that have long, slim whorled leaves.

Oriental lilies, on the other hand, have flowers that are outward and downward facing and flower in late summer, including the very appropriately named hybrid ‘Stargazer’ lily whose outward-facing flowers appear to be looking up.

Stargazer 1

The Oriental lilies are more fragrant than the Asiatic so they are a better choice if that is what you desire in your garden or home. Both are great options for cutting and look lovely in containers with lower growing plants surrounding them. In addition, when grown in containers they can be swapped out with other plants after blooming or grow both groups in the same planter for a succession of blooms.

However, the bane of any true lily grower’s existence is the Lily leaf beetle, Lillioceris lilii. Both the larvae and the adult Lily leaf beetle feed on the foliage of true lilies, in fact they can totally defoliate a plant in a matter of days. This pest was first documented in the United states in Cambridge, MA, in 1992. In the subsequent years it became a major agricultural and economic pest of growers. The Lily leaf beetle is also known as the Scarlet lily beetle due to its bright red coloring.

lilt-leaf-beetle_8_985960008

This insect lays its eggs and completes its entire life cycle on the same plant and can cause damage to both the stems and leaves. The bright orange-red, oval eggs are laid in groups of about 12 on the underside of the leaf in May. In 7-10 days the eggs will darken and then hatch out, allowing the larvae to feed on the underside of the leaf before moving to the upper leaf surface and the buds. They can be hard to control with insecticides as they use their own frass (excrement) as a barrier to cover themselves.

In another two weeks they will drop to soil to pupate emerging a week and a half later as adults.  The adults will continue to defoliate and weaken the plant. Neem can be used as a control but must be applied every 5 days or so. Scouting and handpicking are often the best option and I find that holding an open container below them as I scout helps to catch them if they attempt to drop to the ground. Fun fact: they will make a squeaky noise if squeezed or disturbed.

If you don’t enjoy the monitoring that is required to deal with the Lily leaf beetle or the disappointment of walking past your flower beds only to discover that your lilies have been stripped clean you may want to consider planting another dependable perennial bulb: the daylily.

Flower bed

Daylilies used to belong to the same family as the true lilies, Liliaceae, were reclassified in the family Asphodelaceae in the genus Hemerocallis. Since it was first formally described by Carl Linnaeus in the mid-eighteenth the Liliaceae family kept expanding until it encompassed over 300 genera and 4500 species. Most of these were grouped into Liliaceae simply because they had six tepals and a superior ovary. From 1998 to 2016 a phylogenetics (evolutionary history and relationships) study by the Angiosperm Phylogeny Group was key in recognition of the family Asphodelaceae. Within Asphodelaceae is the sub-family Hemerocallidoideae and the genus Hemerocallis in which resides the daylily.

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The ephemeral blooms of the daylily give it both its common name and Latin name as Hemerocallis comes from the Greek words hemera (day) and kalos (beautiful). To keep daylilies blooming longer I remove any spent flowers and also any of the large, bulbous seed capsules that may appear. Daylilies will grow in full sun or part shade in most soil types although like it slightly acidic, perfect for Connecticut gardens. A bit of a 5-10-5 fertilizer at planting and then each spring when growth appears is all that it needs.

The one pest of daylilies that I have to deal with each year is the metallic-brown Oriental beetle (Anomala orientalis). The adult beetles are attracted to the open blooms and will nestle themselves right down into the center of the blooms.

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Its another pest that I control by handpicking, dropping them into a container of insecticidal soap. I don’t mind though as this activity gets me up close and personnel to the beautiful blooms and also reminds me to deadhead as I go along.

Susan Pelton

All images by S. Pelton, UConn

Black knot of plum and cherry, caused by the fungus Apiosporina morbosa, may be overlooked during the growing season when the leaves are hiding the galls, but this time of year they are hard to miss, especially when they are as abundant as they are on the tree in the photo below.

BlackKnot.Plum

UConn Photo

This is a serious disease of these trees and can eventually kill susceptible varieties. Management options include sanitation, resistant varieties and properly timed fungicides.

Where manageable, prune out all galls during the dormant season and dispose of them off-site, burn or bury them. This is because even removed galls may still produce spores that can cause new infections. Prune  6″ below the visible edge of the gall because the fungus can be invading the wood in that area prior to gall development.

This disease can affect both orchard and ornamental varieties of plum and cherry but some of the tart cherries are less susceptible. Native wild cherries are hosts of the disease and provide a reservoir of inoculum for orchards and ornamentals. It’s helpful to remove those nearby where possible. For new plum plantings (fruiting/orchard), ‘President’ is highly resistant. Moderately resistant options include ‘Methley’, ‘Milton’, ‘Early Italian’, ‘Brodshaw’, ‘Fellenberg’, ‘Shiro’, ‘Santa Rosa’ and ‘Formosa’. ‘Shropshire’ and ‘Stanley’ are considered quite susceptible.

Here’s how disease develops: Infections occur in the spring on new growth from spores produced on the surface of 2+ year old galls. Spores are produced and spread during rainy weather and shoots must remain wet for a period of time for the spores to germinate and initiate an infection. Infections can occur at temperatures of 50°F or higher when water is present for the required period of time. Over the course of the first summer, a small greenish brown swelling develops. By the end of the second summer, the gall or knot becomes hard, rough and black. These galls begin producing spores the following spring. Galls expand in size each year until the branch is girdled (killed all the way around) and then they die. Once a twig or shoot is girdled, the portion beyond the gall can’t get any water or nutrients and dies as a result. Sometimes, larger branches and trunks can become infected, presumably through wounds.

What if you have a susceptible tree and want to prevent this disease? If you know you have a source of infection (hosts with galls nearby, either wild or on a neighboring property) and you’ve had some infections, keep up with the monitoring and pruning, fertilize and water as necessary to prevent stress, and use preventive fungicides, such as lime sulfur during dormancy (organic option) or chlorothalonil or others labeled for this disease. Other than lime sulfur, applications should be made as directed on the label beginning at bud swell and until new terminal growth ceases.

More information on this disease and its control: Black knot fact sheet

By J. Allen

 

‘An herb whose flowers are like to a Lions mouth when he gapeth.’
Copious Dictionary in three parts by Francis Gouldman

After the 5th mildest February in Connecticut on record for the past 113 years it felt as if we were going to just saunter into spring this year. Walking around the yard on the first day of March I saw the usual signs of late winter including the new buds of Hellebore peeping through last year’s old foliage and even a brave little slug that had emerged from the soil.

But the next day March came in like a lion with winds gusting to 74 mph at the Ledge Lighthouse in Groton courtesy of a Nor’easter that also brought snow and drenching rains, days later we had 12-18” of heavy, wet snow across the state and today, another 6-10”. Fortunately, hellebore is able to withstand a little bad weather.

Helleborus is known as winter rose, Christmas rose, and, most familiarly to me because of when it blooms, Lenten rose. Its scientific name was given by Carl Linnaeus in 1753 and comes from the Greek ‘helléboros’ which breaks down into heleîn ‘to injure’ and borά ‘food’ due to the toxic nature of all parts of the plant. Two kinds of hellebore were known before 400 BCE:  the white hellebore of the Family Melanthiaceae was believed to have been used as a laxative by Hippocrates and the black hellebore, melanorrhizon (black-rooted), a member of the Ranunculaceae family. It is the latter group that most garden hellebore belongs to, one that also gives us Delphinium and Clematis (below), Buttercups, Ranunculus, and Anemone.

Hellebore originated in the mountain areas and open woodlands of the Balkans but some species also come from Asia (H. thibetanus) and the border of Turkey and Syria (H. vesicarius). In the centuries since hellebore has found its footing in gardens around the world where it continues to be a favored choice as a ground-cover with dark, shiny, leathery leaves.

It is so popular that Helleborus x hybridus was chosen the 2005 Perennial Plant of the Year from up to 400 nominations by the Perennial Plant Association. Plants are chosen by the PPA for their low-maintenance, wide range of growing climates, multiple season interest, availability, and relatively pest and disease-free care. It’s no surprise that Hellebore made the cut.

Helleborus by Dawn Pettinelli

Image by Dawn Pettinelli

It grows in USDA zones 5a to 8b which makes it very well-suited to Connecticut even though it is not native. It can tolerate shade to part-shade and does well in moist, well-drained soil with a pH range of 5.7-7.0.  Lower pH levels can lead to calcium and magnesium deficiencies. Interestingly, once established, hellebore is very drought-tolerant and even drooping leaves will bounce back unharmed when they are re-hydrated. Due to the fact that its leaves contain nasty-tasting alkaloids it does not get eaten by deer or rabbits and is considered toxic to humans and animals when ingested.

Helleborus orientalis late winter

 

Those same alkaloids can be a problem for people with sensitive skin so it is wise to wear gloves when working with hellebore. I trim the foliage back in late winter, at the start of March if there isn’t any snow cover, so that the emerging flower buds aren’t hidden by the old growth.

If Botrytis cinerea, a grey mold, was a problem on hellebore foliage then infected plant material should be removed in the fall so that it doesn’t overwinter.  Late winter is also a good time to apply a slow-release, balanced fertilizer that will ensure ‘blooms’ that will last for a month or more.

 

I say ‘blooms’ because what appears to be petals are actually tepals that protect the small, barely noticeable flower buds. Sepals are usually green but when they are similar in appearance and color to petals they are called tepals. Other plants that have colored tepals are Orchids, Day lilies, Lilies, Lily of the valley, Tulips, Magnolia and Tulip poplar.

On the hellebore the vintage-looking colors of the tepals range from a pure white to a dusky rose to a deep, almost black, plum. Most tepals become green-tinged as they age and many are veined, spotted, or blotched with shades of pink, purple, or red. The 2-3” ‘blooms’ generally hang or droop down so it is sometimes hard to see the nectaries that provide food for the early pollinators.

There are few insects that bother hellebore but one is the Hellebore aphid which will feed on sap from the flowers and foliage, excreting the honeydew that may lead to the growth of sooty mold. Cucumber mosaic virus can be vectored by feeding aphids and shows itself in light and dark green mottling on Hellebore foetidus.

HL

Image by RHS

 

 

H. foetidus, also known as stinking hellebore or dungwort is found in the wild in southern and western Europe in addition to cottage gardens. Its foliage gives off a pungent smell when crushed and it has another insect pest particular to it, the Hellebore leaf miner, which, as its name suggests, will tunnel into the foliage creating the damage shown to the left.

 

 

There are many commercially available varieties of hellebore and hybridizing has created a color palate that now includes reds, grays, yellows, and greens. The Picotee variety have narrow margins of a darker color. Semi- and double-flowered hellebore have two or more extra rows of tepals and the anemone-centered variety have a ring of shorter curved petals closer to the center which drop off after pollination. A visit to your favorite nursery or garden center is sure to provide you with many selections.

Helleborus by Lisa Rivers

Image by Lisa Rivers

You can put them into the ground as soon as it is workable. As Hellebore do not grow more than 18” high and have flowers that hang down they are best appreciated when viewed from close proximity. Plant them in an area that you walk past often and enjoy them for years to come.

Susan Pelton

All images by Susan Pelton unless noted

Did you notice off-color leaves on your broadleaved evergreens, such as azalea, rhododendron or Andromeda last year?  These popular landscape shrubs are sometimes attacked by lace bugs and their feeding damage results in small, yellow to brown flecks on the leaves. When there are many of these, the whole leaf, and even the whole shrub, can look off color from a distance.

Lacebugdamage.bugwood

Leaf discoloration caused by the feeding of lace bugs. Photo credit: William Fountain, University of Kentucky, Bugwood.org

What are lace bugs? They’re insects in the family Tingidae and have piercing and sucking mouth parts. They are small – the adults are only 2-3 mm in length. They are quite distinctive looking. Adults have flattened bodies with lacy looking wings that give them their common name. The species on broadleaved evergreens appear black and white. Nymphs are quite dark in color, up to about half the size of the adults, depending on their growth stage (instar) and are covered with dark spines.

 

It’s easy to miss these pests as the cause of leaf discoloration because the feed and reproduce on the lower leaf surfaces. They pierce leaf cells and suck out the juicy contents, resulting in cell death. So a lot of this type of injury due to a high population can result in reduced photosynthesis that in turn leads to poor plant health, leaf drop and reduced flowering.

Lace bugs that attack broadleaved evergreens overwinter in the egg stage. Eggs are laid in the leaves of the veins, mostly on lower leaves, and then covered by the female with a cement or varnish like material. Spring hatch occurs typically in May in the northeast. Nymphs begin feeding immediately and go through five nymphal stages or instars before becoming adults. Under favorable conditions, the entire life cycle may be completed in one month. Depending on lace bug species, there may be 2-4 generations per year in Connecticut.

To protect plant health and also to prevent unsightly discoloration of the leaves, monitor for lace bugs early in the season on susceptible plants, especially if they have evidence of injury from the year before. Nymphs and adults can be sprayed off plants with a strong stream of water or they can be treated with horticultural oil or insecticidal soap. Both of these products must coat the pests to kill them so thorough coverage of the leaf undersides is required. Inevitably, some individuals or eggs will survive so a second application may be necessary. Prevention of damage before it gets too severe is important because leaf discoloration will persist for a year or more.

Both azalea and rhododendron lace bugs are more likely to build up to high, damaging populations on plants in sunny locations. The Andromeda lace bug can cause a lot of trouble in both sunny and shady sites.

As mentioned above, there are a number of susceptible plants found commonly in northeast landscapes. The lace bugs have quite narrow host ranges as shown below:

               Lace bug species                                                          Host plants

Andromeda lace bug Japanese Andromeda, Leucothoe
Azalea lace bug Azalea and mountain laurel
Rhododendron lace bug Rhodendron and mountain laurel
 

By J. Allen

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