Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Heavy metal containing doai
Reexamination Certificate
2001-02-09
2004-08-03
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Heavy metal containing doai
C514S492000, C514S493000, C514S494000, C514S495000, C514S496000, C514S498000, C514S499000, C514S501000, C514S502000, C514S503000, C514S504000, C514S505000, C514S574000, C514S918000, C514S919000, C504S100000, C504S101000, C504S116100, C504S187000, C504S189000, C424S407000, C424S195170, C106S015050, C106S018360
Reexamination Certificate
active
06770674
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a repellent for molluscs. More particularly, the present invention relates to a mollusc repellent, which is environmentally friendly being both non-phytotoxic and harmless to non-target animals, and therefore suitable for use in sustainable agriculture, where the use of toxic chemicals is unacceptable.
BACKGROUND OF THE INVENTION
Slugs and snails are major pests of agriculture in many parts of the world. One particular species of slug, the grey field slug, Deroceras reticulatum, is a common horticultural and agricultural pest in Australia, which causes extensive damage to agricultural crops and garden plants.
Significant crop damage by slugs and snails also occurs in the United Kingdom, Northern Europe, the Middle East, North and Central America, South East Asia, Japan and New Zealand. In many cases, the rise to pest status of the slug in question is a consequence of change—either in distribution (as in the case of accidental or deliberate introductions) or in agricultural practice.
In the recent past, fields awaiting seed planting were subjected to a thorough ploughing which actually resulted in the destruction of slug populations submerged beneath the surface of the soil. This maximum tillage of the soil, though, was found to destroy many beneficial characteristics of the soil structure. More recently, in order to reduce expenditure involved in such thorough ploughing and to overcome the difficulties associated with ploughing in muddy, boggy soils, the practice of minimum tillage and the use of drill holes has increasingly been adopted prior to seed planting. The advent of minimum tillage has contributed significantly to the level of slug populations rising to pest status.
Slugs are a major agricultural pest causing significant crop damage because they bury themselves in the soil and then move into the drill holes into which new crop seeds have been planted. Once the seed has been placed in the drill holes, the slugs attack the seed and eat the inside essentially leaving an empty husk, thereby potentially destroying the whole planting. There is therefore an urgent need for a method of protecting seeds from destruction by slugs prior to the seeds being planted.
There are several other instances where a solution to deal with slug populations is required. For example, in order to control weeds and reduce moisture loss by evaporation, it has been common practice to employ sheets of black polythene laid on the ground around the plants and under organic mulching material. The problem associated with such sheets is that they have to be dug up to dispose of them, they are unsightly and they do not allow passage of water through them. Clearly, the use of such material, which is non-biodegradable, is environmentally unacceptable.
One solution to this problem, which is the subject of Australian Patent No. AU-B-64756/94, has been to employ recycled newspaper waste by reconstituting it into matting, in the form commonly known as “weed mats.” Such matting is environmentally friendly since it employs a recycled resource which naturally decomposes. The problem encountered in the use of such matting, however, is that the recycled paper mat is attacked by slugs present in the soil upon which the matting is laid. This attack reduces the effective lifespan of the matting thereby making such a slug barrier unattractive to consumers. In addition, the laying of such matting is very labour-intensive and time-consuming and it would be preferable if the time interval between successive applications could be extended as much as possible. None of the molluscicides presently available on the market are suitable for this application since their efficacy reduces rapidly on contact with water and so would be ineffective in extending the lifespan of the weed mats.
Another case where slugs present a problem is in the agricultural practice of growing brussel sprouts. These crops present one of the few instances where slugs actually move up onto the plant and shelter in the plant itself, rather than stay in the soil and attack the root system. The problem presented in this case is that a slug repellent is required which is non-phytotoxic as well as being harmless to human beings, the eventual consumers of the crop. A further problem is that the slug repellent cannot be in the form of a pellet, but rather in the form of a spray since the repellent has to coat the leaves of the plant. Preferably, the slugs must be prevented from climbing up onto the plants at a very early stage because once they have done so, it has previously been found to be very difficult to remove them. It has been proposed that growers confronted with this problem may use a surfactant repellent such as CeTAB, cetyl tertiary ammonium bromide. However, the efficacy of this repellent is short-lived, since the compound is soluble and washes off in the rain or during overhead irrigation.
As was also mentioned above, one of the ways in which mollusc populations can achieve pest status is that they can be accidentally introduced. One such mode of accidental introduction is where molluscs attach themselves onto the hulls of ships which move from port to port. One way in which such accidental introductions could be prevented is for a mollusc repellent to be applied to the ship's hull thereby preventing the initial harbouring of the mollusc. In the United States, a considerable problem has been encountered in the control of the introduced Zebra mussal, which attaches itself to the inlet and outlet pipes of cooling systems for industrial power generators. This mollusc has now reached plague proportions. To solve the mollusc problems encountered in these two aquatic situations, care has to be taken to apply a mollusc repellent that is not soluble and does not endanger aquatic life. None of the known mollusc repellents would be useful in this application all being either too soluble or too toxic.
Chemical methods (i.e. the use of molluscicides), involving the use of stomach poisons for the control of these pests, are well known. Molluscicides containing metaldehyde and methiocarb have been in use for some time, but these are themselves toxic to non-target animals and human beings and in the form of pellets, they also deteriorate upon exposure to water and in particular, rain and are not sufficiently durable as long-term repellents.
The use of metal complexes in molluscicides was first disclosed in Australian Patent AU-B-22526/88 entitled: “Aluminium(III) and Iron(III) complexes exhibiting molluscicidal activity”, in the name of Henderson et al. In one of their studies, these inventors compared the relative toxicities of some aluminium and iron salts and chelates and their efficacies as stomach poisons by injecting known amounts into the gut lumen of molluscs and they found that the metal chelates were more toxic than their corresponding salts. Metal chelates were also first trialed by Henderson et al as contact-action poisons. In one particular study, Henderson used the metal chelate, FeEDTA, as the toxic agent, finding it just as effective as various salts of Fe(III). (Henderson, I. F. et al, in “A New Group of Molluscicidal Compounds,” BCPC mono., (1989), 41, “Slugs and Snails in World Agriculture”, pp 289-294 eds. Henderson, I. F., British Protection Council, Farnham, U.K.). More recently, Australian Patent No. 683405 entitled: “Ingestible Mollusc Poisons,” disclosed a terrestrial mollusc stomach poison containing as the active ingredient either ferric edetate or the ferric hydroxy-ethyl derivative of edetic acid. These workers have also shown that mixtures of iron salts such as ferric sulphate, ferric chloride or ferric nitrate when mixed together with disodium EDTA or EDTA, as such, are toxic to the slug species, Deroceras reticulatum. The present inventor has also developed a stomach-action molluscicide, disclosed in Australian Patent Application No: 689399, containing the oxodimer, [EDTA-Fe-O-Fe-EDTA]4- as the active ingredient wherein the bait formulation itself was found to
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