Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
2000-10-02
2003-02-04
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
C424S409000, C424S406000
Reexamination Certificate
active
06514512
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a pesticide delivery system and improved methods for enhancing the activity of pesticides by improving delivery to target organisms.
BACKGROUND OF THE INVENTION
Pests, from microbial pests to insect pests, destroy inordinate amounts crops. Improved methods for protecting plants from pests are therefore desired since they would increase the amount and stability of food production. However, pesticides can be difficult to apply, and expensive to maintain after application. Applying toxicants as dry pesticides called dusts is not desirable because it leads to uncontrolled drifting of potentially dangerous chemicals. Applying toxicants in liquids as pesticidal sprays leads to less drifting than dust applications. Nevertheless, regardless of the formulation and application method, the efficacy of a toxicant primarily depends upon its delivery to the target organism.
Pesticidal sprays typically leave residues on plant surfaces. These residues represent an inefficient manner for contact with insects and other pests. Poor pesticide delivery leads to sub-lethal doses of pesticides. Often times, even with adequate spraying or delivery, residues from conventional pesticidal sprays delivered by a water carrier alone do not provide a proper (e.g., lethal) dose to an insect. Efficacy of a pesticidal residue on a plant surface requires that the residue remain on the surface long enough to contact a pest. Surfaces such as leaves, bark, soil, and wood may undesirably absorb pesticide residues and therefore lower the effectiveness thereof. In other words, pesticides loose their effectiveness when applied to sorptive surfaces since contact with pests is inhibited.
Moreover, pesticide application can result in reduced photosynthesis. Generally speaking, pesticide sprays cause a short-term and long-term reduction in the rate of CO
2
uptake (necessary for photosynthesis) and enhance leaf senescence. Thus, although plant survival may increase with a pesticide application, decreased transpiration and decreased photosynthesis undesirably occurs. Photosynthesis and transpiration in plants are positively linked in that a decrease in transpiration generally leads to a decrease in photosynthesis.
In perennial crop production such as tree fruit, flower buds for the subsequent year are initiated while fruit are developing for the current growing season. In practice, a plant may or may not produce flower buds for the subsequent year. One of the many biochemical cues to develop flower buds is the rate of photosynthesis and the availability of photosynthetically derived carbohydrates for flower bud development.
The availability of carbohydrates is limited by the photosynthetic capacity of the plant and the pool of carbohydrates is partitioned between the competing carbohydrate needs of the woody tissue, leaf tissue, developing flower buds and developing fruit. If photosynthesis is limited during the flower bud initiation period, flower bud initiation is reduced and fewer flowers are produced the following season. Reduced flower number results in reduced fruit number. In the subsequent year, the tree has a reduced number of fruit and it develops excessive numbers of flower buds because it lacks the competing developing fruit when flower buds are initiated. The alternating production of large and small numbers of fruit is an undesirable condition known as “alternate bearing”.
A related problem to alternate bearing is called “excessive fruit drop”. Normal fruit drop occurs when, simultaneously, the fruit is developing, tree growth is occurring, and flower buds are being initiated. Photosynthetically derived carbohydrates become limiting to all the growing tissues at this time in the growing season and the plant aborts the developing fruit, and limits the initiation of flower buds. When pesticide application deleteriously effects or diminishes photosynthesis, fruit drop is excessive.
Particle carriers for pesticides are generally suitable for control of soil-borne pests. They are not frequently used for foliar control of insects on plants due to difficulties associated with sticking to the foliage, impeding photosynthesis, and/or consequent susceptibility to removal by wind, rain, or other disturbing forces. Particle carriers for plant protection are not necessarily efficient or economic in view of these difficulties.
SUMMARY OF THE INVENTION
The present invention provides a pesticide delivery system and improved methods of delivering pesticides to target organisms. The present invention provides methods of increasing the amount and/or effectiveness of a pesticide or other pest control agent delivered to a target organism compared to conventional methods. The present invention also provides methods of delivering a pest control agent to a plant and simultaneously increasing the photosynthesis (or at least not diminishing the photosynthesis of the plant).
In one embodiment, the present invention relates to a pesticide delivery system, containing a continuous film having a thickness from about 1 &mgr;m to about 1,000 &mgr;m and noncontinuous areas having sizes less than about 100 &mgr;m, the continuous film containing a particulate material wherein at least 90% by weight of the particulate material has a particle size of about 10 microns or less, and a pest control agent at least partially coating the particulate material.
In another embodiment, the present invention relates to a method of delivering a pest control agent to a target organism, involving the steps of applying to at least a portion of a surface of a plant an effective amount of finely divided particulate material at least partially coated with the pest control agent, the particulate material containing from about 25% to about 100% by weight of a heat treated particulate material, wherein the partially coated finely divided particulate material as applied permits an exchange of gases on the surface of the plant and the partially coated finely divided particulate material forms a continuous film over the portion of the plant surface to which it is applied, and a maximum average size of openings in the continuous film is less than about 100 &mgr;m.
In yet another embodiment, the present invention relates to a method for making a pest control film, involving the steps of combining a volatile liquid, a pest control agent, and a particulate material wherein at least 90% by weight of the particulate material has a particle size of about 5 microns or less to form a slurry; applying the slurry to a substrate; and permitting at least a portion of the volatile liquid of the slurry to evaporate thereby forming the pest control film comprising pest control agent coated particulate material on the substrate, the pest control film containing from about 0.01% to about 10% by weight of the pest control agent and from about 90% to about 99.99% by weight of the particulate material, wherein the pest control film permits an exchange of gases between a horticultural substrate and the environment.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to pesticide delivery systems and methods of delivering pest control agents to target organisms. The methods may involve applying particulate materials containing at least one pest control agent, which may form a film, on a plant thereby increasing the effects of the pest control agent. The deleterious effects of pests on the plant are reduced or eliminated while photosynthesis is not diminished.
Photosynthesis is a process by which photosynthetic plants utilize solar energy to build carbohydrates and other organic molecules from carbon dioxide and water. The conversion of carbon dioxide to such organic molecules is generally referred to as carbon fixation or photosynthesis. The effects of enhanced photosynthesis are typically observed by increased yields/productivity, e.g., increased fruit size or production (usually measured in weight/acre), improved color, increased soluble solids, e.g. sugar, acidity, etc., and reduced plant temperature. Non-diminished photo
Glenn David Michael
Puterka Gary J.
Sekutowski Dennis G.
Engelhard Corporation
Keller Raymond F.
Levy Neil S.
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