Floriculture Greenhouse Update

Late Blight caused by Phytophthora infestans – a very destructive and very infectious disease killed tomato and potato plants in gardens and on commercial farms throughout the eastern U.S. during 2009. Late blight occurs at some locations in the Northeast each year, however in 2009 infected plants were distributed through large local retail stores throughout the region (Ohio to Maine) during June, and outbreaks were reported over this entire region by early July. Never before had such an extensive distribution of infected plants occurred, especially so early in the season. This, combined with the cool, wet growing season and the exceptionally contagious nature of the disease during cool, rainy, windy weather all contributed to a disastrous year for farmers. Garden retailers can help prevent the spread of late blight in gardens and on farms this growing season and provide customers with the facts about this disease. Grow your own transplants from seed or purchase locally grown plants Late blight is not seedborne in tomatoes (however, it is tuber-borne in potato), so tomato plants started from seed locally would be free of the disease. Growing your own transplants from seed or purchasing from a reputable local grower will ensure a healthy start to the season for your customers and local farms. Provide disease-resistant or tolerant varieties       Tomatoes: Disease-resistant or tolerant varieties of tomatoes exist, however seed is in limited supply this year. ‘Mountain Magic’, ‘Plum Regal’, and ‘Legend’ are three varieties with resistance or tolerance to late blight. Note that the variety ‘Legend’ is the only late-blight resistant variety for which seed is readily available this year. In addition to late blight, each year tomatoes become infected with early blight and Septoria leaf spot, which look very similar. If possible, also provide tomato plant varieties that are resistant or tolerant to early blight for your customers, such as the varieties ‘Mountain Fresh’, ‘Mountain Supreme’, and ‘Plum Dandy’ and others.       Potatoes: Purchase certified, disease-free seed potato from a reputable source, and ask your supplier about their source of seed and if it was inspected in the field for late blight. Seed potato from the northeast are less likely to carry the disease. Inspect transplants for signs of disease If you purchase plants to sell, inspect all transplants for stem, petiole cankers or leaf blight as long as plants are on the shelf. Teach your staff what to look for, using the web-links below. If you suspect a late blight infection, use your Plant Diagnostic Lab to confirm if late blight is present. Know the FACTS for Staff and Customers Train employees and provide information to your home gardening customers. * Potatoes that freeze or fully decompose will not carry the pathogen over winter. * Tomatoes will not carry late blight over the winter, because freezing kills the whole plant. *  Tomato seed, even from fruit that was infected with late blight, will not carry the pathogen, so no need to worry about the tomatoes left behind in the garden or compost pile. Certain perennial weeds can become infected with late blight, but none of their above-ground tissues live through the winter. *  Late blight will not survive on tomato stakes and cages. * The biggest threat for overwintered disease in New England is on potatoes. In the spring, advise home gardeners to inspect last year’s potato plot and any compost or cull piles for volunteer potato plants that might come up. If they find potato plants, pull them out and put them in the trash or destroy them. If tubers were infected and survive, then the late blight could grow upward from the tuber, infecting the stem and producing spores when weather conditions are favorable. These spores could then disperse to other tomato and potato plants. * During the growing season, pay attention to pest alerts to learn about whether late blight has been observed in New England, and what actions you need to advise to customers. Pest alerts will be updated on the UMass Extension Vegetable Program Website, www.umassvegetable.org   

Photos: Symptoms on stems, leaves and fruit (Cornell) Photos, FAQ, Fact Sheets (Cornell)

Tina Smith, University of Massachusetts

When choosing plants for retail sale, trial gardens can help growers decide which plants to grow and provide information to customers. Dr. Douglas Cox, University of Massachusetts reported some observations on some new and recent introductions made on plants growing in a small trial garden run by Durfee Conservatory at UMass, trial gardens at Elm Bank, Dover, MA and plantings of his own in Sunderland, MA.    

Here are excerpts from the article: Alyssum ‘Snow Princess’ (Vegetative) The heat tolerance was hard to evaluate the summer, but ‘Snow Princess’ did indeed have a long flowering season starting at planting in mid-May through to October. We cut our plants back once and they quickly recovered to rebloom very well. Plants are compact (4-6” tall) and are excellent spreaders. Angelonia ‘Serena’ (Seed) ‘Serena is not a new plant but it remains the principal seed-propagated Angelonia. In my opinion, the two best characteristics of Angelonias are the vigorous and continuous blooming once the plants are established and the long life of each flower stalk which can extend many weeks. Based on my experience it’s clear that success with ‘Serena’ starts with seeding. Germination temperature should be 68-70°F and irrigation should be carefully managed to avoid overwatering. Seed should not be covered. Angelonias are often thought of as heat-loving plants. Over the years I have found that cool temperatures at planting outdoors do slow development of ‘Serena’, but by the middle or end of June, the plants really take off. Gomphrena ‘Fireworks’ (Seed) I think Gomphrenas are very useful garden plants because they require very little maintenance, minimal deadheading, and the individual flowers last for may weeks. ‘Fireworks’ is a much larger plant and has larger flowers than the familiar Gomphrenas. This plant may be a tough sell to the average consumer because these plants in packs and small containers may be too small to flower, so some promotion with pictures may be necessary. Read more about trial results with photos in the complete article including Cuphea ‘Matchmaker’, Ipomoea ‘Illusion Emeral Lace’ and ‘Midnight Lace’, Petunia ‘Pretty Much Picasso’, Zinnia ‘Solcito’ and Zinnia ‘Zahara’. Note that the companies in the article are the sources of plant material for the trials and are not necessarily that of the breeder.

Elm Bank Trial Gardens: David Fiske is the trial garden manager at Elm Bank.

There was a great marketing idea from a local grower in a recent Green Profit email newsletter that I thought worth sharing, with permission from Tina Bemis. Tina Bemis of Bemis Farms Nursery in Spencer, Massachusetts (town of about 12,000) are expecting more than 800 children for their annual egg hunt this year. Their new goal is not so much to get more kids, but to convert more of their parents into buyers.

Suzi McCoy from the Garden Media Group in Chadds Ford PA spoke on Emerging Garden Trends 2009 at the UConn Perennial Plant Conference. She highlighted the following top 11 Garden Trends for 2009 growing season:

Growers are shipping hardy mums and ornamental cabbage and the weather is unusually warm for this time of year. There have been several situations where the ornamental cabbage arrived at a retail garden center looking great only to have a scorch appear on the leaves a few days later.

Closed trucks on hot days may be stressing the ornamental cabbage, resulting in a scorch on the older/bottom leaves of the plants. Be sure the plants are watered adequately and vent the body of the truck if possible.

Photo of Damage 

Paul Lopes

As growers order goods for the upcoming growing season, they are asking about how to comply with container labeling regulations read about in the trade magazines. The law requires that plants offered for retail sale show specific information. There have been laws in place for many years regulating the labeling on consumer goods. The purpose of the law is to assist consumers in comparing similar products by using uniform and consistent price and quantity information on the product package, or in advertising and signage. This law applies only to retail sales of products to consumers and not to transactions between wholesale suppliers and retailers. Retailers, though, through the normal course of business, may seek assistance from suppliers in providing the required information.

Summary of information needed to comply:

Declaration of Identity:  the common or Latin name of the plant or simply a generic term for the plant material, i.e."mixed annuals"

Declaration of Net Content:  an accurate weight content of the container measure or count. This includes the volume or weight of cells. Measures such as quart and gallon are permissible. However, all measures must be in English and Metric.

Declaration of Responsibility:   the identity and location of the vendor, distributor or retailer who is responsible for compliance with the Uniform Weights and Measure standards. The required information may be provided now by signage or by pot labels.

Link to 8 page publication, "Industry Guide to Marketing Container Plants" (PDF) which contains a complete explanation of the industry guidelines with examples of plant labels.

Tina Smith