Stink bugs

Green Stink Bug (R. Bessin, 2000), KYU.edu

Green Stink Bug Nymph (R. Bessin, 2000), KYU.edu

The center has been receiving a higher number than normal of calls and emails about stink bugs. The nymphal stages are appearing now feeding on all types of fruits and vegetables. Stink bugs have a piercing/sucking mouth part used to stick into plants and produce to eat. Their feeding results in damaged vegetables and fruits and plants. All stink bug are shield-shaped and have  five segmented antennae. They are in the family Pentatomida, Greek for five segments referring to the antennae. Stink bugs have barrel-shaped eggs the adult female lays in groupings called rafts, on the underside of leaves. Eggs hatch into nymphs that gather around the raft of empty eggs until they molt into their second stage. Each stage after hatch and molts are called instars. Stink bugs have five instars until reaching adulthood. Eggs are laid during June and July and typically take five weeks to reach maturity. The highest number of populations will be during September until we have cold weather and frost. Adult will over-winter in leaf litter and other protected sites. These same adults will emerge on spring when temperatures are a steady 70 degrees F. and begin the annual cycle again. There is only one generation a year in the Northeast.

There are 55 different species of stink bugs in Connecticut, 16 are predators that feed on other insects. The remaining 36 are plant feeders. these are the ones gardeners typically notice and are not happy about finding in their gardens. Damage to fruits and vegetables are from their piercing/sucking mouth parts injected into the  produce as the insect sucks up the juices. Control measures are handpicking, row covers to keep the insects off of the plants and searching for and crushing egg rafts earlier in the season.

Connecticut has a new invasive stink bug from Asia. The Brown Marmorated Stink Bug was first found in the U.S. in 1998 in Pennsylvania. It has quickly spread east and north to us. BMSB can occur in high numbers damaging crops and is also quite a nuisance as it seeks over-wintering shelter in homes and buildings. Exclusionary measures of caulking and screening openings, such as vents and crevices will keep them out of the house.

brown marmorated stink, psu.edu

-Carol Quish

BMSB later stage nymph, Penn State Univ.

BMSB Nymphs, Penn State Univ.

 

Farmer’s Market Time Again

Farmers and greens.

Spring is in full swing and the seasonal farmer’s markets are starting to open up to sell the fruits, vegetables and products of our local farmers. The variety and quality are outstanding. Everything from in-season asparagus, spinach and greens to soap, mushrooms, cheeses and preserves. Wool natural and dyed are animal products often sold too.  Farmer’s markets give the producer access to consumers that normally would not be have access to their farm. Farmers do sell to grocery stores, but that involves a middle man and the prices becomes higher or the farmer makes less money. Farmer’s markets give direct contact to the grower where people get to meet the person growing their food. Larger markets are a one stop shopping experience with numerous growers at one site. For a 2012 list of Connecticut Farmer’s Markets organized by the CT Dept. of Agriculture, click on http://www.ct.gov/doag/lib/doag/marketing_files/certified_fm_by_county_05-04-2012.pdf

Recently I traveled to Baltimore, Maryland to visit my daughter and she was very excited to take me to her farmer’s market “under the highway and next to the prison” at 7 am on Sunday morning. The highway over head provides protection from rain and sun. This historic market and bazaar is 35 years old with many vendors including meats, fish, cheeses, plants and even arts and crafts. 8,000 people visit on a typical Sunday between 7 and 12. We brought the camera to share the many offerings  on a sunny morning in mid-May.

-Carol Quish

Hand spun and dyed wool.

Bison meat frozen and as jerky.

Live Maryland Crabs.

Beautifully artistic goat cheeses and cheese pies.

Many varieties of mushrooms.

Rhubarb and Ramps!

Many varieties of potatoes.

Basil plants in six packs.

 

Starting Something

Silene stenophylla, regenerated from a 32,000-year-old seed.
(Photograph: National Academy of Sciences)

The dry little speck that develops into a magnificent plant is one of those miracles that happens so often that it’s easy to take it for granted. But, if we stop and consider the way plants guarantee that a new generation will carry on their genes, we have to marvel at the elegance of nature’s design. Protected by a tough coat, seed can tolerate conditions much harsher than its living parent could ever survive, and it can wait years for the proper conditions to germinate. In the case of Silene stenophylla, proper conditions were scientists removing its seed from a 32,000 year-old squirrel burrow in the Siberian permafrost and growing it. This “delicate” arctic campion grew, bloomed and set seed after millennia of patient dormancy. Other reports of Jerusalem date palm and lotus seed remaining viable for a mere thousand years is testament to the phenomenal adaptation and resilience of plants. (At the other end of the spectrum, some tropical seed remains viable only briefly, and must be sown fresh for good results.)  In order to make management of a crop easier, agricultural seed has been selected to germinate all at the same time, a characteristic that would be disastrous for wild species. Ordinary garden seed, collected the previous year and packed and stored in dry conditions, is a valuable resource for gardeners.

Growing plants from seed allows the gardener a much broader range of plant choices than you’ll find at your local garden centers. With all the offerings online, in seed catalogs or on the racks in the big-box stores, the choices can be overwhelming. When selecting varieties, consider not only appearance, but yield, disease resistance and flavor. Gardeners’ reviews in internet forums can be useful in making a decision.

Tomato seedling 'High Tower' (Photo: Rutgers)

As the time for starting seeds for the vegetable garden approaches, a few pointers may be helpful:

• Start tomatoes on St. Patrick’s Day, or thereabouts (Eight weeks is standard lead time before planting in the garden, but if mid-May is still too chilly, plants can always be held a couple more weeks.) The majority of garden vegetables can be started from seed at this time. Cabbage can wait a few weeks, and for the vines, (cucumber, melon, squash, etc.) delay indoor planting until the last week of April, because setting out these heat-loving plants too early will only retard their growth.
• Root crops should be sown directly in the garden.
• Growing annual and perennial flowers from seed is an economical way to grow large numbers of plants and also to try unusual varieties. Be aware that some perennials require stratification (periods of cold that break dormancy) before they will germinate.
• Seed saved by friends and neighbors in your area are often a good bet. They’ve been tested by others who have about the same conditions as yours.
• Start small seeds in flats and larger seeds in cell packs, using commercial potting soil. (The garden books advise sterilizing the cell packs if they’ve been used before, and also using sterilized growing medium; I do neither and have never had a problem.) Garden soil can contain weed seeds and pathogens; potting mix is the safer choice.
• Don’t trust your memory; identify flats with popsicle sticks labeled with indelible marker.
• Germinate seeds in a warm room. Bottom heat aids germination; a table over a baseboard or radiator is excellent, as long as it’s not too hot.
• Cover germinating seeds with a sheet of plastic to retain moisture. (Dry cleaner’s bags work well, held in place with something light – I use chopsticks.) Monitor closely to be sure soil is damp, not wet. Remove plastic as soon as seeds break the surface. Allow one week beyond the germination times stated on the seed packet. If germination is disappointing or absent, resort to Plan B.
• The humidity that is conducive to seed germination is also the perfect environment for the growth of fungi and bacteria that can attack seeds or seedlings in a condition called damping off. Keep soil moist, but not wet; excessive moisture is the primary culprit of this disease. A small fan running on slow speed (placed well away from the seedlings) or a slightly open window on warm days will help by circulating air and keeping surfaces dry.
• Move sprouted seeds immediately to the brightest light available. A sunny window is good; or artificial lights (fluorescent or LED) hung on a chain can be positioned a few inches from the growing plants and moved as necessary.
• After sprouted seeds have their first set of true leaves, they may require thinning. Plants that are too crowded will compete with each other and none will flourish, so don’t skip this step. Cutting off unwanted plants with small scissors is preferable to pulling because it won’t disturb delicate roots.
• When plants outgrow their cells or small pots, move up to a 2.5-3” pot, using a plant stake or plastic spoon to separate and lift the seedlings. Water thoroughly with a dilute water-soluble fertilizer.
• Vine crops (cucumbers, melons, squash, etc.) are best started in peat pots because they can be transplanted without disturbing their temperamental roots. Peat pots are mushy when wet, so at planting time, soak them well, tear them gently open and plant directly into the ground. Trim off any pot that will protrude above the soil; this will cause wicking action that can rapidly rob moisture from the plant.
• Harden off plants before planting out in the garden, gradually exposing plants, over the course of a couple of weeks, to increasing sunlight and cool weather.

For those who haven’t tried it, growing your own plants from seed is a gratifying experience – there’s no better way to tune in to a plant’s requirements and hone your horticultural instincts, and it’s an economical way to try new varieties and keep your garden interesting.

J. McInnis

 

Good Night Irene and Tomato Trials

Compared to many New England (and East Coast) residents, I am very thankful that except for some water in the basement and a large ash tree that uprooted and fell almost surrealistically in the narrow space between the chicken coop and my three bin composter, we survived Tropical Storm Irene pretty much unscathed.

Tree down from Irene

A lot of my flowers toppled over and that is a bit unfortunate as our local Garden Club holds a flower show every year on Olde Home Day (Labor Day). All members create several floral arrangements, from backyard flower beds and borders, and usually visitors are greeted by several hundred flower arrangements set up in the basement of the Charlton Federated Church. Visitors enthusiastically comment on the veritable explosion of colors, creativity, scents and floral inspirations each year. While we gardeners/floral arrangers are quite resourceful, Irene may have us scrambling a bit this year for ideas!

Coral Fountain Amaranth on its side

The day before Irene was predicted to hit our area, I collected as many tomatoes as I could figuring any I left would be blown off the vine or cracked because of the excessive water. All 14 tomato plants had some ripe or near ripe fruit so this also gave me an opportunity to sample and compare the 10 varieties I grew this year.

The collection before the storm

Cherry tomatoes always rank high as they are most prolific plants, can be snacked on like candy, used in green salads, and also added to any number of hot or cold dishes. ‘Sungold’ tops my list with its sweet, golden-orange, 1-inch fruits. The tomatoes begin to ripen about 57 days after transplanting. Its only fault is that it is thin-skinned so pick all fruits, orange or yellow, before any severe rain event. Despite this minor defect, my garden would not be complete without this most delicious of all cherry tomatoes!

Two other must have cherry tomatoes are ‘Sweet Million’ and ‘Yellow Jelly Bean’. These two, along with ‘Sungold’ not only taste terrific but are just so beautiful grouped together in salads. Also these three varieties are indeterminate in growth habit, which means they just keep growing and producing tomatoes until stopped by a hard frost. Last year I was picking cherry tomatoes well into October. They do have some typical tomato disease problems but because of their indeterminate growth habits, they usually manage to outgrow diseases like early blight, septoria, and anthracnose as long as you can routinely remove any diseased lower leaves. Spraying routinely with a sulfur or copper based, natural fungicide would be prudent as well in our humid, disease-promoting summers.

A new cherry tomato I tried this year is ‘Green Grape’. How lovely, I thought to have orange, yellow, red and green tomatoes in my daily summer salads! These tomato plants are determinate in growth habit, meaning they reach a certain growth stage, set flowers and fruit, and stop growing. At first they seemed immune to most tomato diseases. But then, they seemed to get this one disease that turns the leaves black and kills them. No spotting diseases, like septoria and early blight, for this variety! I thought this was good until I picked off about half of its leaves that were blackened and dead before Irene hit while collecting any potentially ripe fruit. I still can’t quite figure out which fruit are ripe as even the ones that look like they might be are still quite tart. I did notice some fruit changing to a more yellowish-chartreuse color and they tasted more pleasant.

Four small, early to medium, midseason tomatoes I harvested some fruit from were ‘Polfast’, ‘Marglobe’, ‘Champion Hybrid’ and ‘Golden Girl’. In general, the yellow or gold tomatoes are less acidic but still have a pleasing mild, tomato taste. I thought ‘Golden Girl’ was juicy and enjoyable and a nice salad addition and since she is indeterminate in growth habit with a typical maturity of 80 days, I am hoping for a continued harvest for the next month or so.

‘Polfast’ and ‘Marglobe’ have small to medium-sized red tomatoes on determinate plants. ‘Marglobe’ has been around for quite a while because of its sumptuous tomato flavor and disease resistance. The fruits of both of these varieties are most enjoyable and I have used them fresh and skewered with chicken on the grill and as an ingredient in tomato-zucchini casseroles. I will definitely consider growing both again.

‘Champion Hybrid’ gave me about a half dozen tomatoes before Irene and because it is indeterminate in growth habit, I am hoping for a dozen or so more. ‘Champion’ has been producing about one-half pound fruit which are solid and meaty and so far rank number one for my family for BLT’s which we have been indulging in on a regular basis this time of year.

For my canned tomatoes and chili sauce, I am anticipating a decent harvest of ‘Cuore di Bue’ and some unknown plum tomatoes that just sprang up in my watermelon patch. I think these ‘oxheart’ tomatoes, whether of Italian, Russian or other nationality are the absolute best canning tomatoes. They are quite ‘bottom heavy’ with ridges, and range, depending on the variety, from 4 to 8 inches or more across. Oxhearts are meaty, don’t contain many seeds, and are my favorite sauce tomatoes.

Cuore di Bue

All the the oxhearts I am familiar with are indeterminate heirlooms. In fact, I was first introduced to them back in the mid 80’s while working as a horticulturist in a Massachusetts County Cooperative Extension Center. One of my clients had some questions and among them was whether or not I had tried growing a Russian oxheart tomato. When I said no, he promptly brought me one of his plants that he had started from seed brought over decades ago from his native country by his relatives! For many years I saved seed and continued growing this tomato. With time, it seemed to cross with other tomato varieties and the fruits were smaller and the plants more prone to tomato diseases. Now I tend to purchase new seed for different oxheart tomato varieties from various seed houses trying to find a close match. ‘Cuore di Bue’ tastes quite similar but the fruits are smaller. I will continue to grow this one but keep up my search for the original Russian oxheart that was gifted to me.

Aside from being an ardent tomato grower, I also am an ardent composter and you are welcome to join me along with other staff and volunteers at the 1st Annual Fall Compost and Garden Fair. Check it out at http://www.ladybug.uconn.edu!

 

Galls & Burls Explained…Sort of

Trees and other woody plants often have large or interesting swellings on their trunks or branches.   The cause is often difficult or impossible to determine.  Possible causes include fungi, bacteria, insects, mechanical or environmental injury, or genetic mutation.  The terms gall, tumor and burl are commonly applied to describe these abnormal swellings. 

Galls and tumors can be any size or shape and may occur on both woody and herbaceous plants and plant parts.  The swelling occurs as cells divide more rapidly than normal (hyperplasia) and/or due to excessive cell enlargement (hypertrophy).  Burls are generally considered to be large woody swellings that are basically hemispherical in shape.  They often bear many buds and sometimes sprouts.   The burls of black walnut, coast redwood, sugar maple and black cherry are highly prized by woodworkers for their beautiful swirling or ‘bird’s eye’ grain.   This relatively small burl from an apple tree (cause unknown) has an interesting surface pattern and interior grain showing bud traces.

Burl from an apple tree trunk.

 

Tiny brown lines are bud traces.

An individual tree may have one or many swellings.  On this maple tree, the many swellings are of unknown origin.  Often, a tree with large or numerous galls will decline earlier than a tree without them. 

The most common bacterial gall disease is crown gall caused by the bacterium Agrobacterium tumefaciens.   This soil-borne bacterium enters the roots of the host plant through wounds caused by planting, cultivation, frost heaving, insects or nematodes.  The bacteria, upon attaching to the plant cell walls, send DNA that causes production of plant growth hormones into the plant cell where it is incorporated into the plant cell chromosome.  Affected cells begin to multiply at an uncontrolled rate, resulting in visible tumors within 2-4 weeks.   More than 600 plants are susceptible to crown gall.  One of the most common, where galls occur on both roots and stems, is Euonymus, shown in the photo. 

Crown gall of Euonymus.

 

Examples of galls caused by fungi include azalea gall (Exobasidium vaccinii), black knot of plum and cherry (Apiosporina morbosa), and Fusiform rust of pine (Cronartium quercuum).    More information on these diseases is available by clicking on the name of the disease. 

 A close up of a leaf gall on azalea . (Plant Disease Diagnostic Clinic, Cornell University)

Black knot of plum and cherry.

 

 Fusiform rust (USDA Forest Service – Region 8 – Southern Archive, USDA Forest Service, Bugwood.org)

Insects and mites cause some very interesting galls on leaves as shown in the photo.  These usually cause little damage to the host plant or tree and control measures are not normally recommended.  A new theory is being explored by scientists that the swellings associated with these arthropods may in fact be caused by bacteria transferred to the plant tissue during feeding.   Fascinating! 

Hickory gall phylloxera.

 

Galls can be caused by cultural, mechanical and environmental factors including graft incompatibility, wounding, and freeze injury.   Galls on some conifers that vary from small to huge (several times wider than the trunk) are thought to originate when the trees are young seedlings from a single cell and enlarge for many years.  Low temperature injury is suspected, but not proven, as the cause. 

J Allen

 

Visiting Hydroponics

 

C. Quish photo

C.Quish photo

C.Quish photo

On a recent trip to Florida, I visited Hydro Harvest Farms, a hydroponic farm in the town of Ruskin. The barren lot was not the most fertile soil for growing, so the owner invested in vertical planters stacked four high. The growing medium is a soilless mix of perlite and vermiculite. The containers themselves are made of two-inch thick styrofoam, providing insulation to the roots from the heat and occasional cold nights during the winter. Mind a ‘cold’ night in mid-Florida is 35 degrees F. The plants are watered with a nutrient solution providing all the water and minerals the plants need to produce the fruits and vegetables. The solution is delivered through a series of plastic and rubber hoses and sophisticated injection pump system. Pests are controlled using IPM, integrated pest management. Pest insects are indentified, damage evaluated and only then a predator insect will be released to eat the pest insects. Crops grown are a root crops in the base rectangular planter or stand alone box. Potatoes, onion, beets and turnips were on display during this March. Herbs, different lettuce and collard greens filled the stacked star-shaped planters. And there were rows and rows of stacks containing strawberries. This area of Florida is known for its tomatoes and strawberries.  Tomatoes were already harvested and passed and the strawberry crop was just coming in.  Thankfully, my husband doesn’t mind indulging my lust for visiting farms, gardens and botanical adventures, even when we are on vacation.

C. Quish photo

C. Quish photo

 

 

What causes ringspots on Pachysandra?

Pachysandra is a relatively problem free plant and is widely grown as a ground cover in shady areas.  The most common disease is Volutella blight caused by the fungus Volutella pachysandrae.  Dark blotches form on the leaves and the stems.  These increase in size until the plant is killed.  Plants may be killed in patches within a bed.  This disease is most common when plants are stressed by winter injury, insects, transplanting, mowing, drought or exposure to full sun. 

A relatively new disease of Pachysandra in the northeast is caused by a virus known as alfalfa mosaic virus (AMV).  The virus was first reported on Pachysandra in 1982 in New Jersey and is the only virus known to occur on Pachysandra.  Symptoms include chlorotic ring spots and blotches on the leaves.  This virus is transmitted by a number of aphid species including the green peach aphid and others.  It is also transmitted via seed or infected sap. 

Alfalfa mosaic virus has a broad host range that includes over 600 plant species in 70 families.  Symptoms vary quite a bit depending on the host and can include wilting, white spots, stunting, ringspots, mottling, mosaic patterns or necrosis.  Symptom expression is also affected by the weather, strain of the virus and the age of the plant when infected.   Alfalfa plants can be infected without showing any symptoms.  Plants growing near alfalfa fields are at the highest risk of infection. 

Control of this disease is not always necessary.  Prevention by avoiding planting hosts near alfalfa fields is the most effective.  Managing this virus by controlling the aphid vector population has not been successful.  In the case of Pachysandra, removal of symptomatic plants as they appear is the best approach.   Avoid wounding adjacent healthy plants to prevent sap transmission of the virus. 

Scorch can also occur on Pachysandra and is caused by environmental factors including winter injury or drying.  No treatment is necessary; the plants should recover once new growth appears in the spring.

Scale insects may infest Pachysandra.  The three most common are Euonymus scale, San Jose scale and Oystershell scale.  Control measures for these insects include insecticidal soaps, horticultural oils and conventional insecticides.  Another option for severe infestations is to mow the Pachysandra and collect the clippings to physically remove the scales.  New growth will develop from the stolons. 

JA

 

End of season garden chores.

Lately the calls to the UConn Home and Garden Education Center have been about preparing for winter. People want to prune trees while it is still warm. Pruning for most trees is best done while dormant, in winter cold. Trees really don’t need to be pruned at all, just let them grow into their natural shape and size. If you have a tree or shrub that has outgrown the spot where it is planted, than replace it with a more appropriately sized plant. I have seen many houses where the Rhododendron maximum has taken over entire picture windows! I can only wonder how the view from inside looking out appears. Those plants need to be ripped out and replaced with something that has a much smaller height once it reaches maturity.

Lawns are popular topics on the phone and email contacts. Folks, it is too late to fertilize your lawns now. The plants are going into dormancy. This means they are not actively growing. We know they are not growing because we are not having to mow the grass. If the plants are not growing, they are not moving very much water through their roots up to the leaves. Fertilizer is water-soluble, taken in by the plants once dissolved in the water. So if plants are not picking up the water, they are not picking up the fertilizer either. The fertilizer does not just sit there waiting for the plant to take it. The fertilizer will be washed away with rain and snow, moved down and out of the reach of grass-roots in the spring when the plants wake up and start moving water again. Wait to fertilize lawns until you have to mow again in the spring.

Vegetable gardens need to be cleaned up now. Cut back the asparagus and destroy the stalks by burning or bagging and place in the household trash. Asparagus beetles can overwinter on the dead foliage. Tomato and pepper plants need to be pulled and composted deep in the pile. Clean up all other plant material for a fresh start in the spring. Turning the soil over once will expose overwintering pests living in the soil to the colder temperatures and birds to eat. Try planting a cover crop for tilling in during the early spring. Have a soil test done to determine pH and nutrient levels. Lime can be applied in the fall to work all winter if needed. I plant spinach and cold tolerant lettuces in a bed under a hot cap. It is a frame of plumber’s pvc pipe made into a triangle and attached to 2 by 4′s then covered with painter’s plastic sheet stapled to the wood. We attached hinges to one side of the 2 x 4′s and to the side of the raised bed. Once the seeds germinate, their roots will grow as long as the temperatures are not below freezing. The small plants just hang out all December and January, waiting for the about the last week in February when the days get longer, to start growing into strong, large plants. Picking baby leaves begins in the middle of March. I love picking my own fresh salad while standing in a dusting of snow!

Other end of season garden chores include digging the tender bulbs, tubers and corms for storage in non-freezing temperature. Dig gladioli, dahlia tubers, canna and caladiums. They can be stored in damp peat moss, saw dust or sand. I keep mine in a wooden box in the hatchway  of my home. This area stays between 40 and 5o degrees F, perfect for these plants. I am even trying to save my ornamental sweet potato vine tubers. I will let you know how that turns out! As for herbaceous perennials, I cut them back to the ground to prepare for winter. This eliminates any disease from next year’s growth and hopefully removes overwintering insects, too. Cleaning up the foliage of this year exposes hiding places and homes of mice, chipmunks, moles and voles. Anything to rid my garden of these critters, I will try. Set old-fashioned snap mouse traps near any holes in the ground you find. I have caught mice, voles and chipmunks all in the same small area.

Happy End of the Garden Year,

-Carol

 

Squash Vine Borers = Zucchini’s Nightmares

Squash vine borer adult, http://www.extension.entm.purdue.edu

Squash Vine Borer larva and damage, photo by Rob Durgy, UConn

Watching my summer squash’s leaves collapse  just about overnight signals a problem. Further investigation proves worthwhile when I find a small, 1/8th hole on the plant’s stem. I cut the stem lengthwise, carefully splitting apart the vine to reveal the hollow vine filled with sawdust like frass. Frass is the excrement of an insect. About 12 inches away from the original hole lurks the offending caterpillar; the larval stage of the Squash Vine Borer. Not a pretty site from where I stand! Along with the insect chewing the inside of the vine, centipedes have also entered the vine feeding on the frass. All of the these insects introduce bacteria causing rot leaving a mushy trail in its wake. This plant is too far gone to save. It is pulled out after I kill the borer making sure I got them all,  then tossed the plant in the compost.

The life cycle of the squash vine borer, Melittia satyriniformis, has one generation per year. The adult is a clear winged moth active during the day.  There are orange and black rings  on the abdomen. The front wings have greenish to black color while the hind wings are clear edged in brown.  The eggs are laid at the base of the plant on the soil. Once the eggs hatch, they burrow into the vine to begin feeding. Adults are appear late June through July and into August. Signs of an infestation are small holes in the vine and piles of frass on the vine and below on the soil. The larva can reach 1″ in length. They mature after feeding for about four weeks at which time they will leave the vine to burrow into the  soil. Once in the soil they will spin a cocoon in which to pupate. They spend the fall and winter in the pupa state until they emerge next summer as the adult moth.

Control measures are too late for my plant and should have been used much earlier in the season. Row covers made of Remay, a poly spun product reminiscent of mosquito netting, is an effective barrier, light-weight when applied over plants at the beginning of the season. The edges must be pinned down or buried in the soil to prevent the adult insects from crawling under the fabric. The idea is to exclude the adult moth from laying eggs at the base of the plant. Once the plant flowers, the Remay should be removed to ensure bees and other insects are able to reach the flowers for pollination. Turning over the soil at season’s end will expose overwintering pupae to the elements, and hopefully succumb to the cold. Another turn of the soil in the spring will further disrupt their protective site. Pull and destroy plants as soon as they finish producing to possible larvae from entering the soil. Chemical controls are either carbaryl (Sevin) or permethrin applied to the vines once per week starting the last week in June and continuing until the end of July.

If you do find frass and a hole in the vine, cut lengthwise splitting the vine until you find the boring caterpillar. Remove it then put the vine back together and mound soil on top of the damaged area. It might recover!

_ Carol

(cc) 2005, Rasbak.

 

Tomato Pith Necrosis

This summer we had an interesting tomato disease in the diagnostic lab.  It’s tomato pith necrosis, caused by the soil-borne bacterium Pseudomonas corrugata. 

Necrosis and wilt symptoms on tomato plant caused by tomato pith necrosis.

The earliest symptom is chlorosis or yellowing of the younger leaves.  As the disease progresses, leaves may wilt and become necrotic (dead).  Infected stems may or may not have visible dark lesions.  The sample received in the lab this summer didn’t have this symptom.  The primary symptom in this case was wilting and necrosis of the upper part of the plant. 

To investigate further and to check for wilt diseases of tomato, the lower stem was cut in half longitudinally.  The characteristic symptom of tomato pith necrosis, a chambered or hollow pith or center of the stem, was observed.  In some cases, this is white as shown in the photo.

White chambered pith in tomato stem.

More advanced bacterial colonization results in the browning and softening of this tissue.  The vascular system may also be brown.  This tissue is in the outer part of the stem and the sample’s vascular browning is pictured below.  Two wilt diseases of tomato caused by fungi, Fusarium wilt and Verticillium wilt, both cause browning in the outer, vascular tissue of the stem, but not in the pith. 

Stem section with both vascular and pith browning.

White and brown (decayed) chambered pith.

One symptom that is quite distinctive but that was not readily apparent in this case is the development of many adventitious roots on the outside of the stem near the chambered pith areas.  Adventitious roots are roots that develop from above-ground plant parts.  Sometimes, the infected tomato plant is able to grow out of this disease. 

 Conditions that favor tomato pith necrosis include low night temperatures, high nitrogen fertility and high humidity.  It often occurs when the fruits are nearing mature green, or just before they begin to redden. 

To prevent this disease, do not over-fertilize with nitrogen and space, prune and stake tomato plants to promote good airflow around them, reducing humidity. 

JA