Aphids

Introduction

Aphids weaken and destroy plants by sucking out the life-giving sap from leaves, stems and fruits. Plants attacked by aphids get yellow leaves and start to wilt, slowly dying. Aphids are also transporters of viral and bacterial plant infections.

Description

Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, (not to be confused with “jumping plant lice” or true whiteflies) are small sap-sucking insects, and members of the superfamily Aphidoidea.Aphids are among the most destructive insect pests on cultivated plants in temperate regions.

NATURAL PREVENTION

  1. Spot the aphids. Aphid damage is recognisable by telltale signs of cottony-looking threads around new buds and leaves. Some aphids prefer older growth. Aphids are also known as “plant lice” and they hang around in bunches, making them easy to spot
  2. Make Organic Aphid Sprays. Create an aphid spray using a mild detergent and water, or make a soapy garden spray. Spray every two to three days over a period of a week – you must spray the aphids directly for this to be effective. You can also use garlic spray as an effective aphid controller.
    • Consider using neem oil mixed with water. Or, add neem oil with OHN (garlic + ginger + molasses). Dilute the ingredients in water and spray directly below the leaves (where aphids hide). Spray repeatedly 3 times per week for a plant with serious aphid damage.
  3. Squash them. Provided you don’t mind quite a bit of patrolling and squishing, you can be very effective at reducing the aphid population by manually squashing them. This is labour intensive and likely you will miss some, but combined with organic sprays, this can be very effective. Wash your hands well with soap after each session, or wear garden gloves.
  4. Companion plant. Plant your favourite roses alongside aphid-discouraging plants. Aphids dislike garlic, chives, onions, mint, petunias. Aphids love nasturtiums. Roses grown with garlic plants or chives are much less prone to aphid attacks and both have a beautiful flower of their own during flowering season.
  5. Release ladybirds. Ladybirds (ladybugs) feast on aphids. You can purchase the larvae in packs online or from specialist nurseries. Follow the release instructions carefully – they should be released right near the food (the aphids) and must never be released in an area that has been sprayed with pesticides.
  6. Blast them with the hose. Depending on how sensitive your plant is and your water usage restrictions, you can blast aphids off the plant with the jet stream of a hose.
  7. Try flour. Sprinkle flour over the aphids using a sieve or flour sifter. The flour will coat the aphids and they will drop off.
  8. Dig banana peel into the ground. Cut-up banana peels or use dried banana pieces for this. Dig the cut-up peel or dried pieces 2.5–5 cm into the ground around the base of every plant that aphids are attracted to. The aphids will soon be gone.

PESTICIDES

 

What could be wrong with my roses?

WHAT IS WRONG WITH MY ROSES?
Whenever one thinks that the roses in a garden are not growing well or do not look healthy or even abnormal it is best to correctly identify the problem and the cause before attempting to spray with a pesticide. Very often it is a growing problem that reduces the natural resistance to insects and diseases. The illustrations below should help in the identification.

Deficiency Symptoms

Rose leaves inform the observant gardener of the plant’s wellbeing or of its problems. Large, deep green leaves indicate an active root system, well aerated, with enough moving water and adequate nutrients available for absorption. Stem length and flower size can be expected to be superlative. Smaller leaves can indicate heat stress and insufficient water, while discolouration of the leaves shows a deficiency of nutrients – see section on fertilising.

The most common, clearly noticeable deficiencies are of nitrogen and iron.

NITROGEN DEFICIENCY

Nitrogen deficiency is indicated by pale green-yellow leaves and shoots. On an average rose bush, approximately 20 to 30 actively growing shoots extend, in total, by about 5cm per day. This growth requires a considerable amount of nitrogen. Being water soluble, nitrogen is leached out of the soil more quickly than any other nutrient, particularly in sandy soil. The only way to bring a plant out of such a deficiency is by adding a fertiliser high in nitrogen (N). Within 10 days of application and watering a distinct difference in the greening of the leaves and sprouting should be evident. Using manure takes twice as long to bring about a change and with well rotten compost even longer.

IRON DEFICIENCY

It is indicated where leaf veins remain green, but the areas in between gradually turn light green to yellow, and almost white in severe cases. An iron deficiency does not necessarily mean that there is no iron in the soil, but rather that it cannot be absorbed by the roots – usually the result of insufficient aeration due to soil compaction, over-watering or waterlogging. Without a good supply of oxygen in the root zone, micro-organisms are inactive and do not convert iron, manganese, boron, copper, sulphur and other essential trace elements into a form that can be absorbed by the roots.
Sudden loss of leaves (leaf drop caused by disease, removal of too many active leaves when cutting long-stemmed blooms, or hail) disturbs the balanced flow of sap, leaving the roots unable to absorb and transport trace elements. Signs of deficiency become apparent in the leaves within days.
When the soil contains relatively high percentages of lime or sodium (natrium combinations), causing high alkalinity, absorption of some micronutrients, including iron, is blocked. Acid organic material such as peat moss and milled pine bark helps regulate this problem, together with a handful of flower of sulphur sprinkled around each plant once or twice a year. (The condition will compound if caused by alkaline irrigation water.)

HIGH pH

Various deficiencies occur due to a very high pH of 8.5. This high pH can be reduced by applying a good handful of flour of sulfur around each bush, and then watering it in.

MAGNESIUM DEFICIENCY

A magnesium deficiency can be overcome by spreading Epsom salts around the bushes or by using Ludwig’s Vigorosa® fertiliser.

TO RECTIFY DEFICIENCIES
Ensure adequate aeration of the soil, and treat plants with trace elements in chelate form (for easy absorption by the leaves and roots), or add them to the spray cocktail. The most popular commercial product is Phostrogen, which contains all required nutrients. To correct deficiencies almost immediately, wet the leaves and drench the soil with 50g of Phostrogen in 10litres of water for about ten medium-sized bushes.

A common practice is the annual application of a tablespoon of Epsom salts (magnesium sulphate). Magnesium is an important trace element, responsible for the formation of chlorophyll, and is beneficial in alkaline soil where sulphate helps acidify the soil. In good, friable soil and normal conditions, this treatment, while not harmful, is not necessary.
Excellent, quick results are achieved after fertilising with LAN (limestone ammonium nitrate) at a rate of between 50 to 80g per mature bush.

Problems arising from extreme weather conditions
Much of this has to do with what is commonly known as sap flow, actually it is the circulation of water and dissolved minerals (nutrients) flowing upwards from the roots into the tip of every leaf. The strongest flow is to the highest points to the leaves which are exposed to the sun most and where evaporation is the strongest. These vertical bundles of tubes known as the xylem are on the outside of the wood. Part of the water is lost due to evaporation and the other part combines minerals and sugars created by photosynthesis to form amino acids. This sap is thicker than water and cannot be lost through evaporation. It is transported via the phloem, a porous tube, downwards and sideways to all growing parts of the plants and to the roots. The phloem is on the outside just beneath the bark. The important part one needs to understand is that the leaf acts as a sort of valve. Without leaves there is no downflow and a stagnation of the water that was pushed upwards. The sun heats up stagnant water in xylem to the degree of killing cells and tissue causing what is called sunburn.

SUNBURN
Although sunburn is not a disease in itself, it causes a secondary disease known as stem canker or coniothirium. This is caused by bacteria and no remedial sprays are available. It causes ‘die-back’ or rather ‘die–up’ of part of the rose bush, or even the entire bush. A secondary fungus and bacteria settle in dead tissue almost immediately, and soon attack the surrounding healthy tissue as well. Black to purplish blotches become visible on the stem. The xylem capillaries through which sap is transported are blocked or severed at this point and, once the dead tissue has encircled the stem, the above section shrivels and dies.

Sunburn occurs on the lower parts of the stems, usually on the curvature just above soil level. It can happen in early August, when the stems are still bare after pruning, and the sun rapidly warms frozen tissue after a frosty night. In regions that expect late frost, it is advisable to spray after pruning with a solution of 1 part lime sulphur to 5 parts water, or use limewash. The residual whiteness reflects sunlight.

Sunburn occurs more often and with more devastating results in the heat of summer, when the lower parts of the plant are not shaded by a canopy of leaves and when water in the surrounding soil is allowed to heat up because of insufficient mulch or cover. Sudden leaf drop (caused by black spot, spider mites, hail etc.) can slow down the sap flow so much that normal cooling processes – liquid moving through the capillaries – does not take place.

If blotches are apparent but have not spread too much upwards (they never move downwards), it is still possible to retain the affected stems by sealing them with Steriseal. The stems will put on new growth and, with the sap flow restored, callus growth around the edges of the infected areas will prevent the disease from spreading. Such branches can be removed at a later stage during routine pruning, by which stage new basal stems will have taken over.

Another, often devastating problem that is caused indirectly by a slowing down and concentration of sap in the phloem is a proliferation of red spider and scale insects.

COLD SNAP
A cold snap in September can burn the tips of soft, new shoots. This happens almost annually in the coldest regions of the country. If the cold is not too severe, it may turn out to be beneficial – by performing a good pinching of shoots, after which rose bushes will sprout very quickly again, and with renewed vigour. However, if the frost is very severe, symptoms of sunburn (described above) may occur.

Climatic conditions and weather patterns play a major role in determining the well being of roses. Preemptive spraying can lessen the impact of adverse weather conditions.

 

Downy Mildew

Downy MildewIntroduction

Downy mildew refers to any of several types of oomycete microbes that are obligate parasiteof plants. Downy mildews exclusively belong to Peronosporaceae.

Downy Mildew is not as widespread and much more dependent on ideal temperatures and moisture conditions to cause devastating results on roses.

Description

Red purple blotches of downy mildew on rose White hair of downy mildew on roses

Downy Mildew symptoms occur on leaves, stems, peduncles, calyxes and petals.

The leaves develop purplish red to dark brown irregular spots or blotches which might be mistaken for spray burns or possibly black spot.

If one is not familiar with the symptoms of Downy Mildew one could easily overlook this until infections have caused leaf drop and deformation of the bud. The biggest problem is the speed with which infection can take place with the resultant devastation of a whole flowering flush.

To visibly identify this disease one needs to pick an infected leaf, fold it at a brown spot and hold it against the light. White “hair’ are visible.

Damage

Downy Mildew on rose Stem burst open due to downy mildew Downy Mildew

The ideal stage for a Downy Mildew attack seems to be when the buds are still green and about pea-size. Germination takes place in the upper two, still soft leaves and soon after, this Mildew enters the peduncle, spreading upwards and blocking the normal sap flow to the bud. The buds are unable to develop normally and are eventually totally distorted and unpickable. The bark of the still soft basal shoots become affected by severe Downy Mildew infection. This is evident from a brown-purplish discolouration of the skin. Soon after it bursts open to release more conidia or to serve as a seasonal hiding spot for the Pathogen. This is why sanitation is so important and it is best to cut out affected parts, remove them from the site, and burn them.

Environment

The optimal conditions for the appearance of Downy Mildew are constant high humidity, low night temperatures and moisture on the leaves. The optimal temperatures for spore germination is between 10°C and 18°C no germination take place at temperatures below 5°C and the spores are killed at temperatures above 27°C. Certain cultivars are more resistant to Downy Mildew than others. The causal agent of Downy Mildew is Peronospora sparsa, this fungus might be on your roses under normal conditions – with a very sparse spore production – until such time that conditions become favourable. The spores germinate within 4 hours in water, enter the leaves, and reproduce in three days. Spores survive on dried fallen leaves for as long as one month.

Areas of occurrence

Downy Mildew was virtually unknown on the South African Highveld until the nineties and even in the cool, moist climate of the Western Cape of South Africa it was not recognized as a problem on roses two decades ago. The main areas that are now suffering from Downy Mildew on and off are in Kwazulu Natal of South Africa

Prevention & Treatment

In practice this means one has to lower the humidity by improving ventilation and aeration. Only by correcting the optimum climatic conditions (or a sudden change in weather – sunshine) will an immediate stop be made to the spreading of Downy Mildew.

NATURAL PREVENTION

Plant roses in full sun. They should receive a full six to eight hours of sun daily.

Plants will grow more robustly and be able to resist powdery mildew better. Shade causes slower moisture evaporation thus creating a breeding zone for powdery mildew and other fungal diseases.

Plant roses in an area with good air circulation and space them well. Moisture evaporates faster. In addition the breeze will dry off the foliage.

Aerate the soil in winter. The roots of roses need an aerated soil; plants are stressed if water logging occurs and stunt new growth, thus being more susceptible to powdery mildew.

Water correctly. Plants that do not receive enough are more prone to fungal infection. Deep soakings, 3 times a week in the hot summer months will suffice. Watering late in the afternoon or evening must be avoided. Any sudden influx of cold air will immediately increase humidity and cause drops of evaporation.

Choose resistant varieties. Roses vary in their resistance to this disease. Use resistant varieties for low maintenance plantings.

The method of picking off diseased leaves to prevent spreading has become an old fashioned method due to the availability of new, disease tolerant roses and effective pesticides that should be used for major infestations.

PESTICIDES

Spot checks and preventative spraying are essential. Effective fungicides should be on the shelf in regions where this disease is prevalent such as Coastal regions and on Inland regions if autumn rains are prevalent. If Downy Mildew breaks out and one is unable to spray within 24 hours it will be too late for curative action coupled with the danger of severely affected main stems which are essential for the next flush.

Protecting the leaves by spraying is effective. During ideal “downy mildew” weather condition, spraying on a weekly basis is essential. The following fungicides are effective to a degree in preventing the spores to enter the leaves as well as killing spores on the leaves. The most common group contains the active ingredient Mancozeb. Of these are very many fungicides registered under various trade names.

The most common:

  • Dithane WG                 mancozeb
  • Mikal M                     mancozeb + fosetyl aluminium
  • Ridomil Gold                 mancozeb + metalyaxyl

Fungicides containing copper:

  • CoppercountN                  copper ammonium
  • Copperoxychloride                copperoxychloride

Fungicides absorbed by the leaves

(These have a partial curative action as they clear the blocked capillaries)

  • Proplant                   proparmocarb
  • Proparmocarb               proparmocarb
  • Benlate                   Benomyl
  • Chronos                  imidazole prochloraz zinc complex

Fungicide to eliminate spores

  • Phytex                   phosphorous acid equivalent

Also see

Peronosporaceae (list of downy mildew genera)

References

Taschner, L. Ludwig Taschner’s Roses 2010:37 ISBN 978-1-77007-803-1

Rust

IntroductionRust on roses

Ludwig’s Roses on: Rust is a disease caused by the parasitic fungus Phragmidium tuberculatumand and some other closely related species. It is specific to roses, and appears in spring and persists until the leaves fall.

Susceptibility to rust varies widely among rose cultivars, and most modern roses are resistant to rust. Rose rust is the least serious of the common rose diseases; black spot and powdery mildew are far more prevalent.

Description Rust on roses

Rust appears as its name implies, as red-orange spots (raised looking like warts) on undersides of leaves and yellow blotches on top surfaces. Infected leaves may fall early.

Generally prevalent during cool moist weather.

Damage

Rust causes the young foliage to curl and distort  – older leaves are not deformed but display the same coloured spots on the top and underside of the leaf  lowering photosynthetic efficiency that results in reduced plant growth and vigour.

If left untreated the foliage will eventually fall off which will set a rose plant back considerably if infestation takes place in spring.

Plants can be severely stunted if they are heavily infected early in the growing season. Rose tissue becomes more resistant to infection as it ages.

Environment

Rust thrives in cool, moist weather (18 to 21 degrees Celsius), especially in rainy, foggy or misty conditions. This disease will develop on leaf surfaces that remain wet for 4 hours (as can occur during summer fogs, heavy dews or extended rains).

Life Cycle, Survival and Dispersal Rust close up

The fungus causing rose rust is, like all rusts, a biotroph:  it infects the host tissues for extended periods without killing them, feeding on the living cells. Like all rusts, it is not able to survive on dead plant material, so must either alternate with a different, perennial host, or produce a resting spore to pass the dormant season.

Phragmidium tuberculatum and several other very similar species which infect roses do not have an alternate host; that is, they only attack roses and pass the winter as resting spores.

The first formed spores (spring spores) infect young stems, causing distortion and the production of bright orange pustules. These in turn infect the leaves to produce dusty orange spores (summer spores) which are spread by wind and initiate further infections. In late summer, the pustules producing summer spores switch over to produce the dark, tough resting spores. These spores survive the winter often adhering to stems or trellises. And then the infection starts over again in spring.

Reproduction of rust spores occurs every 10 to 14 days throughout summer.

Infections may be severe enough to cause serious damage, but this is relatively rare and most infections are light enough not to require control.

Environment

Rust thrives in cool, moist weather (18 to 21 degrees Celsius,), especially in rainy, foggy or misty conditions. This disease will develop on leaf surfaces that remain wet for 4 hours (as can occur during summer fogs, heavy dews or extended rains). Reproduction of rust spores occurs every 10 to 14 days throughout summer

Treatment and Prevention

NATURAL PREVENTION 

Good soil drainage is essential for moisture control; adding organic matter, double digging beds or planting raised beds are effective means in providing a good healthy environment for roses. Also it is best to avoid working in a wet rose garden so as not to help spread rust spores (this is also sound advice regarding minimizing the spread of blackspot and mildew). In humid regions, try to limit wetting the foliage on rose plants while watering and provide good air circulation between plants by spacing them well apart from one another. Prune to keep the centers of rose bushes open for air circulation as this will assist in keeping them drier.

FUNGICIDES

Dithane                     mancozeb

Rose Protector/Rosecare         Propiconazole

Resources

http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=269

http://www.rosemagazine.com/articles02/pages/rust.asp

Botrytis

Introduction      Botrytis    

Prevalent especially during cool, wet weather. The disease is caused by several strains of the fungus Botrytis cinerea and attack blooms and canes, but is rarely seen on rose leaves.

Blooms become spotted, then brown and finally completely rotten, in severe cases the stems can be affected and die back completely.

Description

Botrytis spots Botrytis on roses

During the rainy season, the disease affects rose buds and petals – you may see pink/ red spotted flower petals or the tips and edges of the petals turn soft and brown. The spots look like water spots on the petals, however, the spots are actually caused by the plants’ reaction to the invasion of the fungus at the spot where the petal has been damp. Other times, the flowers simply ball and fail to open, or result in a mess of brown petals. This can be followed by wooly gray fungal spores on decaying tissue. Twigs may die back and large, diffuse, target like splotches form on canes.

Damage 

Different stages of botrytis on roses Botrytis on roses Botrytis damage Botrytis damage botrytis invades  rose plant

Botrytis cinerea causes the still developing bloom to not fully open – moisture becomes trapped between the many petals and rot ensues. An entire crop of blooms can be lost this way. In severe cases – black or caramel-colored, sunken and elongated lesions, with a definite outline, appear on young soft stems causing it to be weakened, girdled, and collapsed at the point of infection followed by wilting of the foliage above the lesion – if favourable conditions continue the entire plant will die.

Environment Botrytis cinerea rose 3 by Magnus Gammelgaard

Rainy and high humidity climatic conditions create just the right mix to bring on an attack of botrytis on roses. Warmer and drier weather takes away the humidity and moisture that this fungus loves to exist in, and under such conditions this disease will usually discontinue its attack. Good ventilation through and around the rose bush helps keep the humidity buildup within the bush down, thus eliminating a favorable environment for the botrytis disease to get started.

Life Cycle, Survival and Dispersal Botrytis cycle

The fungus over seasons on decayed plant material or in infested soil.

Sclerotia are the main structures for field survival, although conidia may over season in the field and can survive a temperature range of 4 to 54°C. The overwintering stage can be spread by anything that moves soil or plant debris and transports sclerotia, mycelium, or conidia.

Treatment and Prevention

NATURAL PREVENTION

Since it is such a prevalent fungus, prevention is the best approach – plant roses that are not susceptible to botrytis blight; reduce the humidity around plants by providing good air circulation, modifying irrigation and reducing ground cover; deadhead any infected flowers immediately and dispose of fallen leaves and petals; prune out infected canes, buds, and flowers and generally maintain good garden sanitation.

FUNGICIDES

No home garden fungicides are available that controls Botrytis. But since this disease is only prevalent for a short period of time – it does not cause long term problems.

Resources

http://www.marinrose.org/botrytis.html

http://web.aces.uiuc.edu/vista/pdf_pubs/623.PDF

http://entoweb.okstate.edu/ddd/diseases/rosebotrytis.htm

Powdery Mildew

Introduction       Powdery mildew on rose leaves

Powdery mildew is one of the most common foliar diseases of roses. It is caused by the fungus Podosphaera pannosa. The conspicuous white growth can affect all aerial parts of the plant, but mainly new soft growth – producing microscopic spores that spread the disease. High humidity is favourable for infection, as well as plants growing in areas where air movement is poor or on plants that are grown in too much shade.

Description Sp pannosa 7by Magnus Gammelgaard

A white, powdery fungal growth on the leaves and shoots. Both leaf surfaces can be affected.

There may be discolouration (yellow, reddish or purple) of the affected parts of the leaf, and heavily infected young leaves can be curled and distorted.

Mildew growth may also be found on the stems, flower stalks, calyces and petals.

Damage

Powdery mildew on a peduncle Powdery mildew on roses SONY DSC SONY DSC

Powdery mildew not only causes the foliage to curl and distort making it unsightly but the fungus also lowers photosynthetic efficiency that results in reduced plant growth and vigour.

The growing tips and flower buds may be malformed but the death of an entire plant is rare. Plants can be severely stunted if they are heavily infected early in the growing season. Rose tissue becomes more resistant to infection as it ages.

Severely infected foliage can prematurely fall off.

Environmental conditions

High relative humidity is favourable for infection. Temperatures bewteen 16-27 degrees Celsius make conditions favourable for the development and spread of the Fungus.

Plants growing in shaded areas or where air movement is poor or the soil is dry can be prone to Powdery Mildew.

Unlike many other fungal diseases, extended periods of leaf wetness are not required in order for the spores to germinate. This means that powdery mildew is often a problem during dry summers.

Life Cycle, Survival and Dispersal

Powdery Mildew Sp pannosa 7by Magnus Gammelgaard

All powdery mildew fungi require living plant tissue to grow. On perennial hosts such as roses, powdery mildew survives from one season to the next as vegetative strands in buds or as spherical fruiting bodies, called chasmothecia, on the bark of branches and stems.

The powdery mildew fungus overwinters as dormant mycelium in bud scales and rudimentary leaves within the dormant buds. (That is why we recommend that all the leaves are removed after winter pruning so that the leave axil does not harbor the dormant spores.)

Infected buds break open in the spring and develop into systemically infected shoots. The fungus sporulates on these shoots, producing large numbers of microscopic spores (conidia) in chains that are carried by the wind or other means to healthy rose tissue where they infect the upper and lower leaf surfaces, thus initiating a new disease cycle.

Rose powdery mildew spreads during the growing season by means of microscopic, air-borne spores produced on the powdery growth.

Treatment and Prevention

Natural prevention

Plant roses in full sun. They should receive a full six to eight hours of sun daily.

Plants will grow more robustly and be able to resist powdery mildew better. Shade causes slower moisture evaporation thus creating a breeding zone for powdery mildew and other fungal diseases.

Plant roses in an area with good air circulation and space them well. Moisture evaporates faster. In addition the breeze will dry off the foliage.

Aerate the soil in winter. The roots of roses need an aerated soil; plants are stressed if water logging occurs and stunt new growth, thus being more susceptible to powdery mildew.

Water correctly. Plants that do not receive enough are more prone to fungal infection. Deep soakings, 3 times a week in the hot summer months will suffice.

Choose resistant varieties. Roses vary in their resistance to this disease. Use resistant varieties for low maintenance plantings.

The method of picking off diseased leaves to prevent spreading has become an old fashioned method due to the availability of new, disease tolerant roses and effective pesticides that should be used for major infestations.

Pesticides

Spot checks and preventative spraying are essential. Effective fungicides should be on the shelf in regions where this disease is prevalent. Protecting the leaves by spraying is effective.

During ideal “powdery mildew” weather conditions, spraying on a fortnightly  basis is essential. The following fungicides are effective to a degree in preventing the spores to enter the leaves as well as killing spores on the leaves. The most common group contains the active ingredient Mancozeb. Of these are many fungicides registered under various trade names. Several fungicides are registered for control of powdery mildew. Because of the waxy nature of rose leaves, a spreader added to the spray will give better coverage.

We strongly recommend ‘CHRONOS’, a suspension concentrate fungicide with the active ingredient: Prochloraz zinc complex (imidazole) & Prochloraz equivalent.

The old remedy of treating powdery mildew with a baking soda spray has been shown to be ineffective.

The most common

Funginex                   Triforine

Rose Protector/Rosecare         Propiconazole

Dithane                     mancozeb

Fungicides absorbed by the leaves

(These have a partial curative action as they clear the blocked capillaries)

Proplant                  proparmocarb

Proparmocarb         proparmocarb

Chronos                  imidazole prochloraz zinc complex

When Using Pesticides always follow the instructions.

Resources

http://web.aces.uiuc.edu/vista/pdf_pubs/611.pdf http://apps.rhs.org.uk/advicesearch/profile.aspx?PID=748

<http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7493.h