A fair amount of limb breakage to ornamentals due to ice and snow accumulations may also be seen. Bedding plant producers should keep an eye out for thrips. Some unusually heavy populations have been noted early in some locations. Mesurol has a 2 (ee) recommendation and has been working well.
It is too early to tell what effect if any the season had on overwintering insects on trees and shrubs. We have had a few very cold nights but the fall was relatively mild. A cold wet spring could reduce pests such as gypsy moth. Cornell Recommendations for Greenhouse are available and have been mailed to enrollees. Tree and Shrub and Turf Recommendation should be available soon.
John Farfaglia
Table of ContentsMultiple applications using the same product year after year are not recommended, which might lead to a resistance problem. In some cases the labels specifically limit the number of applications or amount which can be applied on an area basis. Although these have been generally safe on a wide variety of ornamentals with a few exceptions, it is generally wise to test first on a small area or a few representative plants. Some materials work best when used during the early stages of an outbreak, so monitoring is helpful for timing an application when it can be most effective. The cost of some of these newer "high-tech" products is a consideration, but to some extent this is offset by a long period of residual control and a reduced number of applications. Where mite control has been a problem, resistance is a concern and/or repeat applications are difficult, these materials are worth a look.
Hexygon 50WP
Hexygon is the Gowan Company trade name for hexythiazox, EPA#10163-2Q8. This material is labeled for agricultural/commercial use in nurseries and for "mature ornamental plantings" to control various spidermites, such as spruce, southern red and twospotted. It does not control rust mites. For nursery use, the re-entry interval is 12 hr. It is not labeled for use in greenhouses. The label carries a CAUTION signal word.
Hexygon is in the carboxamide chemical class. It works both on contact and through ingestion but has no systemic activity. Although it is not effective on adult mites it is ovicidal (kills eggs) and eggs laid by treated females will not be fertile. It also controls immature mites sprayed directly or exposed to treated surfaces. This provides a relatively long period of residual control (30 - 60 days, claimed by Gowan). The same active ingredient when used on apples has provided season-long mite control in orchards. It should be used early in season or at early stage of infestation, since it will not act quickly to "clean up" a serious outbreak. Results from trials at the Long Island Horticultural Research Lab and elsewhere also indicate this is true. Plants with low-level infestations and those prone to annual mite problems are good candidates for treatment or preventive application.
When applying to foliage good coverage to both leaf surfaces is important. Hexygon can be mixed with most adjuvants or spreader-stickers, except not with Plyac or household detergents. A company representative indicates that combinations with an organosilicone wetting agent are particularly effective. Test for compatibility before tank mixing with emulsifiable concentrates or other materials. Some sources suggest to avoid mixing with synthetic pyrethroids (e.g. Talstar, Tempo) or other insecticides. Approximate price per 100 gal. of spray: $25 - $50 (1 - 2 oz rate).
Sanmite 75WP
Sanmite (EPA#7969-106) is the BASF trade name for pyridaben, in the pyridazinone chemical class. Sanmite is labeled for general use on all ornamentals in greenhouses, shadehouses and outdoor settings to control various spider mites, such as European red, southern red and twospotted. It is also labeled for control of broad mites, whiteflies and mealybugs. The 4-oz rate has worked well for twospotted mites on roses in a trial at the LIHRL this year, providing control for at least 4 weeks. Incidental control of at least some rust mites and thrips may also be expected, although Sanmite is not labeled for these pests and should not be used for their control. For commercial nurseries and greenhouses, the re-entry interval is 12 hr. The label carries a DANGER signal word.
The company suggests using Sanmite only once per season. Like Hexygon, it is best where mite populations are still low but increasing, although for European red mite is has been used to "clean up" a problem infestation. Eggs are not usually killed and adult mites are not as susceptible as immatures, which may die on contact with a treated surface. For heavy infestations, mites should be knocked down with a separate miticide spray or in a tank mix. Adult whiteflies, however, are very susceptible to Sanmite. The company claims mite and whitefly control for 3 - 6 weeks or more with one application. It works primarily by contact, and there is some absorption into leaf tissue, although it is not systemic.
When mixing, the water-soluble bag should be completely dissolved before adding any spreader-sticker or other adjuvant. The water-soluble bags should not be added to sprays containing boron. As a contact material, coverage to both leaf surfaces is important. Sanmite will suppress some beneficial mite predators and should not be used around foraging bees. Do not mix with sprays containing boron or any adjuvant. Approximate price per 100 gal. of spray: $92 - $184 (2-4oz rate for mites).
Avid 0.15EC
Avid has been around for a number of years, but since it has been primarily marketed to greenhouse growers it has been less familiar to nursery and landscape markets. However, it can be a very effective miticide for nurseries and landscapes when used under certain conditions. The same product used on apples under a different brand name (Agri-Mek) can provide season-long control of European red mite with a single well-timed application. Avid (EPA#s 618-96 and 100-896) is the Novartis (formerly Merck) brand name for abamectin, derived from fermentation of Streptomyces avermitilis, a soil organism. For nurseries and greenhouses, the re-entry interval is12 hr. It has a WARNING label.
Avid belongs to the macrocyclic lactone chemical class and is labeled for control of spider mites and leafminers on a wide variety of ornamentals. Although it has been generally safe on a wide variety of plants (including open flowers), it should not be used on Shasta daisies or ferns. Like all new materials, it should be applied to a small number of plants on a test basis first.
Avid is effective against adult and immature mites but is not ovicidal. It works both on contact and through ingestion. Although not systemic it is "translaminar" and will penetrate the leaf surface of young foliage to provide 2 - 3 weeks of residual control. Since mites feeding on the undersurface of treated leaves can be affected by treatment to the upper surface, coverage isn't quite as critical as with other materials. However, for best results foliage should be tender and not hardened off when Avid is applied - on apples, for example, optimum results are obtained when trees are sprayed within two weeks of petal fall (this still remains to be fully tested on ornamentals). Later applications will probably be less effective against spider mites and leafminers. An adjuvant may help improve penetration into the leaf surface. In one trial at the LIHRL, Avid at 16oz/A provided at least 3 weeks of control of spruce spider mite on Douglas-fir when applied in late spring (without adjuvant). At 8oz/A there was about 1 - 2 weeks of control. Recent trials with 4 oz/100 gal have shown good control on spruce and twospotted spider mites. Approximate price per 100 gal. of spray: $29 (at 4oz rate for mites).
We still have some of the former standby miticides, Morestan (= Joust for nurseries) is labeled for mites, mite eggs and whiteflies on ornamentals. It should be applied under good drying conditions and preferably not during periods of high temperature and humidity. Some plants have shown symptoms of phytotoxicity after treatment - see the label for specifics. Kelthane T/O is labeled for control of a wide variety of spider mites and others, including cyclamen, rust and broad mites. Diazinion can be used on certain outdoor ornamentals to control twospotted spider and cyclamen mites; malathion and insecticidal soap are broadly labeled for control of spider mites on ornamentals - observe treatment precautions when applying insecticidal soap.
Dimethoate (Cygon) can be used to control mites on certain evergreens. Mavrik and Talstar T & O (=Talstar Nursery Flowable for nurseries) are two pyrethroids labeled for control of spider mites on ornamentals and can provide quick knockdown of mite populations. Watch plants treated with pyrethroids for resurgence in mite levels, which sometimes occurs. The same is true for Sevin, which is labeled for eriophyid mites (such as rust mites) but is not effective against spider mites. Finally, horticultural oil applied during the dormant season at 2-4% rates can be used to control a wide variety of overwintering eriophyid mites and eggs of certain spider mites (such as southern red, honeylocust and spruce), or used at lower rates during the growing season to control these pests. Observe label precautions and restrictions when using oil during late spring and summer, since oil application (particularly to stressed plants) has been know to cause injury.
Daniel Gilrein, Cornell Cooperative Extension of Suffolk County
Table of ContentsSome composts have shown disease suppression of soil borne pathogens such as Verticillium, Rhizoctonia, and Fusarium, although it is difficult to determine the extent of suppression which and be expected in the field. Although this benefit may be short lived in some cases, it could aid the plant in getting through the reestablishment process after which the plant's natural defenses can take over.
Soil pH can be modified and changes buffered through the addition of compost. When we used yard-waste based compost the pH of the soil increased incrementally, from 5.5 to 6.5, as the rate of compost was increased from 0% to 50% by volume. The reason for this is that compost, when composted and cured properly, has a pH near neutral. This is true of yard-waste compost as well as compost made from bio-solids. In fact, lime is added to bio-solids to help the composting process as the organisms responsible for decomposting the material work best at a higher pH.
If growing ericaceous or other acid-loving plants, adding too much compost can increase the pH above that which the plants can tolerate. Generally, the micronutrient content of a yard-waste compost is high so if the pH is raised a small amount there should be enough available for plant growth. If a micronutrient deficiency occurs, the soil may need to be acidified to release additional amounts.
We must remember that "all composts are not created equal". Before jumping in and using any compost you're unfamiliar with, it is a good idea to test the pH, nutrients, and possibly heavy metals if the situation warrants it. Compost which has not completed the process can have a very acidic pH, possibly 3.5 or lower. Also, if the pile is not turned often enough, has no coarse material in it, or kept in very high piles, the area below the surface can become anaerobic (depleted of oxygen). The organisms that live under these low oxygen conditions can produce phytotoxic chemicals that can severely affect their health or outright kill them. By aerating and completing the process, the harmful chemicals will be broken down and the product can then be used safely.
Even completely composted and cured piles of organic matter, bark mulch, or finely ground wood chips can turn "Sour" if allowed to go anaerobic. When purchasing these materials look for negative signs such as steam coming from the pile and/or a "sour" smell. This may indicate the material may need to be aerated for a while before use. Just from moving it and spreading it out for a few days will allow the compost to improve. Leaching it with some water may also be beneficial, but be careful not to completely saturate it, filling the pore spaces with water rather than air.
| Symptom | Possible Causes |
|---|---|
| Leaf stippling | Spider mites, leafminers (oviposition punctures), plant hoppers, Lace bugs, nutrient deficiencies, mechanical damage |
| Leaf & flower distortion | Aphids, thrips, mealybugs, cyclamen mites/broad mites |
| Leaf spots & blotches | Leafminers, plant bugs, fungal or bacterial infections, INSV, Physical or chemical injury |
| Yellowing | Scale insects, mites, fungus gnat damage to roots, root rots, low Nitrogen, other nutrient deficiencies, leaf senescence |
| Wilted foliage | Stem-boring worms, fungus gnat damage to roots, root aphids, Root mealybugs, grubs, root rots, high soluble salts, poor irrigation |
| Leaf chewing &skeletonizing | Snails/slugs, caterpillars, beetles, grasshoppers |
| Honeydew, sticky leaves | Aphids, mealybugs, scale insects, whiteflies |
| Leaf drop | Spidermites, scale insects, poor root health |
| Virus/virus transmission | Most common vectors: aphids, thrips, whiteflies |
J.P. Sanderson
Table of ContentsHerbaceous Perennials Production is a comprehensive information source that considers the diversity of situations encountered by growers in businesses of all sizes. The 220-page book maintains a focus on production and contains information that until now was available only in piecemeal form.
It discusses the basics-such as taxonomy and nomenclature, plant hardiness, the physical needs of crops, and types of irrigation systems-as well as cutting-edge, research-based information about perennial propagation and production. The focus is on nursery and greenhouse production of field or container perennials, but the greenhouse plug and bedding plant methods of production are covered as well.
Dr. Leonard Perry has been growing perennials in the United States for twenty-eight years, both in the South and in the North. He has spent summers working in industry and at the reowned Longwood Gardens in Kennett Square, Pennsylvania. Since 1981, he has been with the extension system at the University of Vermont, working directly with the industry and region, speaking at meetings locally and internationally, and touring perennial gardens and nurseries worldwide. His research during his tenure in Vermont has covered all aspects of perennial culture, particularly overwintering and hardiness.
How to Order/Contact:
Herbaceous Perennials Production: A Guide from Propagation to Marketing, NRAES-93, is available for $27.00 per copy (plus shipping and handling) from NRAES (Northeast regional Agricultural Engineering Service), Cooperative Extension, 152 Riley-Robb Hall, Ithaca, New York 14853-5701.
Quantity discounts are available. The shipping and handling charge is $5.00 for a single copy within the continental United States. If ordering more than one book or if ordering from outside the United States, please contact NRAES for shipping costs. Orders from outside the United States must be prepaid in U.S. funds. Major credit cards are accepted, and checks should be made payable to NRAES. For information about quantity discounts, or for a free publications catalog, contact NRAES by phone at (607) 255-7654, by fax at (607) 254-8770, or by e-mail at nraes@cornell.edu.
Long Island Horticulture News, December, 1998
Table of ContentsBenefits From Taking Care of the Root Zone
Soil microbial inhabitants generally thrive when given nutrients, organic matter, air circulation, and adequate moisture with good drainage. Grass plants benefit from the same treatment. And since growing plant roots stimulate the activity of many soil microorganisms, it is easy to see that healthy turf and high microbial activity can complement each other. The benefits of an active microbial population include nutrient cycling and availability, thatch decomposition, and disease suppression. The question is, given real world considerations, how do mowing, aerifying, topdressing, and pest control affect the turfgrass soil ecosystem?
A key component of golf course care is the intensive management necessary to have a grass surface ready for season long play. Heavy traffic can lead to compaction, a problem to plants and microbes alike. High visual quality expectations are difficult to meet a times, especially when microclimates favor disease, or during very hot weather. But sometimes the short term solution to a problem will not be a benefit in the long run. Integrated pest management requires an understanding of the relationships between cultural practices and total plant health.
Mowing
Cutting grass leaves off regularly is a drastic cultural practice. In a natural setting, grass plants flower and set seed without losing their photosynthetic leaves, the source of sugars for new growth of roots and shoots. When grass is cut, there is a temporary cessation of root growth. Taller grass has a deeper root system, giving the plants more drought resistance and surface area for nutrient uptake. Experts think that some grasses, such as bentgrass and annual bluegrass, were adapted to grazing by animals over evolutionary time. As a result, they have become adapted to close mowing height. Since soil microbes thrive on the exudates of growing roots, it follows that higher cutting heights favor a larger, more active microbial population by increasing the root system.
Grass Clippings
Returning grass clippings to decompose provides an excellent nutrient source: the fertilizer analysis of clippings is 5-3-1. The clippings begin to decompose within a week, if conditions favor microbial activity. The nitrogen from clippings can be found in new grass leaves within two weeks when conditions are right. The organic matter promotes microbial growth, with bacteria and fungi converting complex nutrients to simple, soluble compounds that roots can absorb. Organic matter and nutrient recycling are critical to healthy turfgrass, so don't bag the clippings and take them away!
Cultivation and Aerification
Compacted soil layers, poor drainage and bare, dry patches in turf indicate the need for cultivation or aerification. Areas that don'' show such serious problems can benefit from cultivation too. Equipment that removes cores, slices the turf, or drills holes will improve the soil environment for microbes. Better air circulation and drainage will enhance microbial activity, possibly encouraging deeper rooting.
Irrigation
When the soil becomes dry, the beneficial microorganisms cannot maintain the same rate of growth and reproduction. In areas with chronic low moisture, the bacteria and fungi that survive best are the ones which form stable dormant structures. This limitation changes the general population diversity and activity cycles with rainfall. If the root zone is deep and the grass is mowed tall, the turfgrass ecosystem will be more stable during drought.
Fertilization
Too much fertilizer can result in burning, but more subtle problems can also arise. If fertilizers are applied at the wrong time, fast, succulent growth will result that is more susceptible to diseases. A high concentration of soluble nitrogen can reduce the activity of nitrogen fixing bacteria. Judicious use of slow release fertilizers or light, frequent fertility programs lead to healthy turfgrass and a healthy root zone. Natural microbial processes in the soil release nutrients gradually for uptake by the roots. If the carbon to nitrogen ratio is high, such as in dry, brown leaf litter, the microbes need additional nitrogen to continue to decompose the organic matter, degrading cellulose to usable compounds and humus. Without nitrogen fertilizer, the microbes might win the competition with the grass roots for nitrogen, and inadvertently cause yellowing of the turf.
Topdressing
Topdressing of compost, sand, sludges, and/or slow-release fertilizer can make a significant difference in the microbial population. Topdressing provides cover that alters the microclimate in the thatch. In addition, biological control products (derived from suppressive soils) and composts can supply additional microorganisms to enrich the turf grass ecosystem and provide competition with soil pathogens. Combining the application of topdressing with cultivation ensures that materials will penetrate to the soil level.
Application of Fungicides
The products available to control fungal diseases can be very effective in stopping the growth of fungi. In studies with applied beneficial inoculants, certain fungicides can completely prevent growth and reproduction.
Soil respiration is considered a sign of the health fertility of soil. For a short time after fungicides are applied, there is a reduced consumption of oxygen and release of carbon dioxide by the mixed population of soil microorganisms. This reduction in respiration is the result of the chemical toxicity toward the many susceptible species of fungi and bacteria, both target and nontarget. Fortunately, the respiration recovers quickly.
In summary, the turfgrass manager has a powerful set of tools to use in promoting a healthy root zone. Soil microbes are a valuable resource. Nutrient cycling and disease suppression are two very important natural processes. Since the cultural practices that benefit microbes also promote healthy turfgrass, it behooves the manager to make careful investments and decisions.
Source: Jana Lamboy, New York State IPM Program Cornell University Turfgrass Team
It is a good time to step back, and think about what is about to happen. One of the things that have struck me is how rarely anyone looks at pruning in terms of plant physiology. Yet, I am persuaded that if people understood better what happens inside the plant when they prune, they would do a better job on the outside.
When a woody plant is pruned - or loses branches for any reason - two different chemical and physical processes begin: a wound response, and a bud response. The first sets up a chain of actions that work to seal off a wound, and is particularly important for trees because they are committed to single stems. The second shifts the pattern of bud suppression and release, and is particularly important for shrubs that depend on multiple stems.
Wound response is initiated by the sudden presence of oxygen and lack of restriction to cell expansion. The chemical and physical nature of the newly exposed surface is altered, creating a barrier to infection by wood-decay fungi. Plugs then block the affected xylem and phloem that carry water and nutrients up, sugars and other chemicals down. Third, the plant keeps any infection from circling around with a barrier along the rays that go out through the wood in all directions from the center. Finally, especially if it is young or the wound is small, it constructs a complete new outer wall by rolling in callus wood from the sides of the wound.
Through this process a woody plant attempts to seal (not heal) the infected area around the wound, surrounding it with a barrier zone. Since a great deal of energy is required, it is crucial that the plant be able to execute efficient photosynthesis as it works, and that the work time be as short as possible. In fact, recommended care of wounded trees follows these two principles. This is why a clean cut across the face of the branch collar is best, why younger trees and smaller wounds seal better, and why one of the best treatments of a wounded tree is to supply it with 2"/week of water through the drier parts of the season.
Bud response is initiated by the sudden removal of the terminal or apical bud from a branch or larger structure. A plant's form results from a complex interaction between genetics and environment. The genetic component consists first of interacting growth hormones, primarily auxins and gibberellins, that affect individual buds and other tissues. Auxins being transported down from the shoot apex suppress lateral and other buds below it, especially during a shoot's first growing season. Gibberellins transported up from the root apex promote bud release and shoot elongation, when auxin is weak or absent. When you add to this mix the fact that the terminal growing point dies after one year in some species (like birches), and does not in others, you can see how genetics can produce such varied form.
When we prune, then, we remove the inhibiting force of auxins that is responsible for apical dominance, and subsequently alter the plant's structure. Usually, the bud closest to the cut will establish new dominance over the shoot. This is why the question is not "Where do I cut," but "Which bud do I want to release?"
Environmental influence on form comes from the essential competition for light, which all plants try to reach by growing upwards or sidewards. When a plant is shaded, differential growth is triggered by the reallocation of sugars and auxins to the darker side of a shoot. When a plant is illuminated, buds on that side tend to be released because of the increased breakdown of auxins. These two processes mean that, when a plant is trying to reach the light, all the pruning in the world will not keep it from growing in that direction.
Pruning against these genetic and environmental signals is a bit like trying to paddle upstream: you waste a lot of energy, feel frustrated, and don't get very far. Successful pruning works with genetic and environmental constraints. Start by making some careful observations. How is the plant trying to grow? From what part of the plant (top, middle, or bottom) does growth usually begin? What is causing the growth responses seen? How can I use those responses on their causes in making pruning decisions? Once you have answered these questions, Your pruning is sure to improve.
Jerry Bond, Cornell Cooperative Extension, Monroe County
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