Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1999-05-21
2002-08-27
Levy, Neil S. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S405000, C424S776000, C424S195110, C514S506000, C514S552000, C514S549000, C514S937000
Reexamination Certificate
active
06440441
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method of controlling
Sphaerotheca pannossa
(powdery mildew) infection of rose plant by the application of a fungicidal wax ester emulsion, wherein the wax esters are the esterification product of monoethylenic acids and monoethylenic alcohols having between 18 to 24 carbons each and are emulsified in water with surfactants. Preferably, the wax esters are comprised of a mixture of wax esters which are at least 85% identical to the type and concentration of wax ester found in naturally occurring jojoba extract, with a surfactant at a concentration between 1% v/v and 10% v/v of the total wax ester mixture.
BACKGROUND OF THE INVENTION
Over the last thirty years it has been a goal of various government agencies to develop uses for the desert plant jojoba (
Simmondsia chinensis
), especially the extract produced from the jojoba seeds. Due to the jojoba plant's ability to thrive in arid climatic conditions in coarse desert soils and it's life span which can extend up to 200 years, the plant was thought to be particularly useful for developing an agricultural industry in the underutilized lands of the American southwest.
The jojoba plant produces an abundance of seeds with an average yield for a mature plant of about 12 pounds (dry weight). Jojoba seeds contain about 50% by weight of a colorless, odorless oily extract which is commonly referred to as “jojoba oil”. The extract is chemically an unsaturated wax made up of non-glyceride esters having a narrow range of chemical composition. Another natural source for wax esters is spermaceti, a wax produced from the head of the sperm whale. As the sperm whale is an endangered species and interstate sale of its oil was banned in 1973, it is not recognized as a particularly useful source for these wax esters.
Jojoba oil is more than 97% wax esters. Each wax ester is derived from one molecule of a long-chain monoethylenic alcohol esterified with one long-chain monoethylenic fatty acid. The wax esters typically are comprised of carbon chains of 38 to 44 carbon atoms. Suprisingly, the wax ester components of jojoba oil have been found to exhibit superior fungicidal capabilities.
Powdery mildew is the common name applied to one of the most damaging and wide spread diseases in the agricultural and horticultural industry. Powdery mildew is a disease caused by species of several genera of fungus on a number of different host plants. The variety of horticultural and agricultural plants susceptible to powdery mildew disease is large. The disease is called “powdery mildew” because of appearance of the mycelial growth gives a powder like appearance on the surface of the host. The white powdery growth appears on infected leaves, stems, fruit and flower buds. Infected leaves may also appear distorted and fall from the plant. Powdery mildew spores are easily spread by wind to nearby plant tissue and to other plants, resulting in an epidemic if left unchecked.
Sphaerotheca pannossa
is the fungus species which causes powdery mildew infection on rose plants. Powdery mildew infection is prevelent problem in the rose crop industry. This is particularly problematic since this crop value depends on its appearance. In fact,
Sphaerotheca pannossa
infection is known to cause millions of dollars in rose crop damage per annum.
Various chemical compounds have been disclosed which claim suitability for use as a fungicide for controlling powdery mildew infection. For example, U.S. Pat. No. 5,366,995 discloses the use of short chain fatty acids and their salts as a fungicidal agent. The disclosed fatty acids generally have carbon chains of between 7 to 20 carbon atoms and preferably at 18 carbons. None of these application disclose the high molecular weight wax esters commonly found in jojoba extract for use as a fungicidal agent. Further, jojoba extract has been reported as a pretreatment to prevent powdery mildew infection on grape plants (Canadian Patent Application No. 2,103,014). In contrast, the subject invention is directed towards the use of wax esters for prevention and eradication of
Sphaerotheca pannossa
infection of rose plants.
In our studies, it has been surprisingly determined that the wax esters found in jojoba extract are both an inert physical barrier and an eradicant of
Sphaerotheca pannossa.
This discovery gives rise to commercially important applications.
In modern agriculture and horticulture the avoidance of unnecessary environmental loading is a key commercial advantage. Both horticulture oils and fungicides are applied repeatedly during the early stages of the growing season to prevent the powdery mildew infection from becoming established. The oils and fungicides are applied multiple times per growth cycle to prevent powdery mildew infection and then again if powdery mildew appears. Since many crops have two or more growing cycles per year, this leads to yet more fungicidal treatments. As a result, the frequent fungicidal applications lead to a build up of that particular chemical agent in the environment (environmental loading).
Conversely, application of the wax esters of the subject invention can be limited to instances where a powdery mildew infection occurs. Thus, wax ester fungicidal treatments are limited to a few, if any, application per growing season and environmental loading is significantly lowered. Less fungicidal applications also results in a lower cost to growers. In addition, the wax ester fungicidal agent is rainfast after the application has dried. Thus, the wax ester fungicidal agent can prevent
Sphaerotheca pannossa
from infecting a rose plant in a single application but also kills existing infections and then prevents reinfection over time. Jojoba extract has the ability to eradicate
Sphaerotheca pannossa
tolerant or resistant strains that have evolved under current fungicidal protocols. Therefore, use of a jojoba extract as a fungicide is economically efficient and significantly reduces environmental loading.
The wax esters provide a greater degree of safety than horticultural oils and fungicides. Many of the existing horticultural oils and fungicides are generally not environmentally safe in their application. For example, use of petroleum oils and sulfuric fungicidal applications for powdery mildew are restrained under the federal regulations as they have serious environmental ramifications if applied in a concentrated form or in high volume. Further, the fungicides and oils are generally volatile. Thus, use of these materials is hazardous to workers applying the chemical. Another popular fungicide, sterol inhibitors, are also heavily regulated because of their environmental impact and the residues they leave on edible crops. The wax esters used in this invention provide particular stability and are significantly less volatile than horticultural oils. Specifically, the greater degree of unsaturation and the long carbon chains, which are almost twice as long as fatty acid oils, enhances stability and non-volatility. Jojoba extract is a safe and natural application and is not heavily impacted by regulatory laws.
Additionally the wax esters of the subject invention have other advantages which make them a particularly effective as a fungicidal agent for treatment of
Sphaerotheca pannossa
infection in rose plants. For example, the long chained wax esters are generally non-toxic for predator, beneficials and honeybees. The wax ester agent is generally non-phytotoxic at the preferred range of use and, unlike many of the prior art fungicides mentioned above, never “burn” plant tissue. In fact the wax esters have been found to promote photosynthesis and stomatal conductance in the host plant.
SUMMARY OF THE INVENTION
It has been discovered that wax esters having high molecular weight are a particularly effective and safe fungicidal application for preventing and eradicating
Sphaerotheca pannossa
infections on rose plants. This invention provides a method for treating rose plants infected with powdery mildew fungus with an emulsion of wax esters compri
Hicks Scott C.
Siemer Sidney R.
IJO Products, LLC
Levy Neil S.
Townsend and Townsend and Crew
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