Plant protecting and regulating compositions – Seed coated with agricultural chemicals other than fertilizers
Reexamination Certificate
1999-10-19
2001-07-17
Pak, John (Department: 1616)
Plant protecting and regulating compositions
Seed coated with agricultural chemicals other than fertilizers
C504S297000, C504S298000, C504S313000, C504S320000, C514S341000, C514S404000, C514S406000, C514S407000, C047S057600, C047SDIG009, C071S064020, C071S064070
Reexamination Certificate
active
06261996
ABSTRACT:
The present invention relates to a process for the preparation of rice seed for sowing and to pregerminated rice seed.
Rice crops are attacked by a number of pests. A useful method of protecting rice and rice seed and rice crop is to apply one or more phytoprotection products to the seed by different methods such as coating, soaking or dipping. Although it is well-known that dry or ungerminated seeds can be coated with a phytoprotection product and subsequently sown, a common practice is to pregerminate rice seed by soaking the seed in water containing one or more phytoprotection products followed by a period in which the soaked, treated seed is allowed to drain and produce a radicle. (The period during which the seed is soaked, drained and during which a radicle is produced is called the pregermination period and the resulting composition, that is, a seed from which a radicle has been produced before it is sown, is a pregerminated seed.)
This is a most efficient and attractive way of seed treatment, but there remains the problem of the disposal of hazardous waste water despite efforts to minimize the concentration of the phytoprotection product or the volume of the liquid. Another potential hazard of this conventional seed soaking method is the generation of seeds that are treated but unused for any reason. Said unused seeds can be hazardous waste.
Rice seeds are commonly sown by dropping pregerminated seeds from an airplane over a flooded rice propagation area. Webster et al, in the publication
Hilgardia,
1973, vol. 41, pages 689-698, indicate that sowing pregerminated rice seed in such a manner “introduces complications not experienced with seed treatment in other cereals.” Further, the authors point out that the standard practice of soaking rice seed for 24 hours and then draining for 24 hours complicates development of suitable methods of applying phytoprotection products since “the protectant chemical must adhere to the seed in effective concentrations throughout the soaking and planting process to be effective during the initial period of seed germination and seedling establishment.” In an effort to arrive at a suitable method, Webster et al investigated the effects of several protectant chemicals, Difolatan, Captan and Thiram, applied before, after and during the soaking procedure and measured effectiveness in terms of percent stand increase over untreated control. They conclude that application prior to soaking afforded best total stand establishment. Application of phytochemical after soaking was found to give no increase in plant stand, that is, no significant protectant effect. No details as to the temperature or length of soaking time or production of a radicle or size thereof were given. Moreover, the authors' recommendations to treat rice seed with phytoprotection products either before or during soaking, if used with the preferred volumes of seeds according to the instant invention, would generate very large volumes of hazardous liquid waste.
International Patent Publication No. WO 93/01705 describes a process in which seed is coated by a foam and one or more phytoprotection products. According to the method described in this document, there is simultaneously applied to plant seeds: (1) a liquid composition containing at least one phytoprotection product; and (2) a foam formed from a second composition containing at least one non-phytotoxic foaming agent. The two compositions are brought separately into contact with the seeds while mixing to ensure a homogeneous and even coating. WO 93/01705 states that “seeds thus treated may optionally be pregerminated.” The quoted expression is believed to clearly suggest optional pregermination of the seeds after the phytoprotection process and prior to planting (a step sequence which Webster et al found most desirable). Further, the aforementioned problem of unused, treated seed is not obviated by the WO 93/01705 invention.
An object of the instant invention is to provide a highly effective method of preparing rice seeds for sowing.
Another object of the instant invention is to provide a highly effective method of preparing rice seeds for sowing, for example by plane.
Another object of the instant invention is to provide a process for the preparation of rice seed for sowing in large quantities that reduces or minimizes or even avoids altogether the generation of hazardous, unusable seed.
Another object of the instant invention is to provide a process for the preparation of rice seed for sowing that reduces or minimizes or even avoids the problem of liquid waste.
Another object of the instant invention is to minimize the exposure of humans to phytoprotection products.
Another object of the instant invention is to provide a rapid method for the treatment of pregerminated rice seed by a phytoprotection product.
Another object of the instant invention is to provide a method of protection of pregerminated rice seed against fungal pathogens.
Another object of the instant invention is to provide a method of protection of rice seed against insecticidal pests which is effective over a substantial period of time.
Another object of the instant invention is to provide a method of protection of rice seed which avoids the disadvantages of the known methods.
It has now been found that the above objects can be met in whole or in part by the means of the instant invention. These and other objects will better appear during the description of the invention.
There is now provided a method of preparing rice seed for sowing comprising the following steps:
(a) pregerminating said rice seed in water containing substantially no phytoprotection product at a temperature and during a period of time sufficient to produce a radicle having a size such that the said radicle is not substantially damaged in a subsequent seed treatment process; and
(b) mixing the pregerminated seed thus obtained with an effective amount of a phytoprotection product.
A preferred embodiment of the invention is one in which the amount of said pregerminated seed is appropriate for sowing from the air, usually sowed in quantities between about 10 and about 20000 kg, more preferably between about 100 and about 1500 kg. The treatment of such large quantities in such a short period of time and with minimum damage to the grains is an especially difficult problem. Said pregermination process is preferably contained in one or more bags. Bags are water permeable containers that are optionally deformable, preferably able to contain between about 10 and about 1000 kg of seed before soaking. Sowing from the air generally entails the loading of an aircraft, preferably an airplane, followed by flying over the field to be sown and distributing the seed to be sown. Another type of aircraft suitable for sowing is a helicopter.
Another preferred embodiment of the invention is that the size of the radicle is between about 0.1 and about 15 mm, more preferably between about 1 and about 5 mm.
The mixing of said seed with the phytoprotection product generally takes place at or near (e.g., within about 50 kilometers of) an airport or airstrip, preferably within the legal boundaries of an airport used by said planes for sowing. Said mixing can optionally take place in a mixing apparatus that is in or on a truck, trailer, or other movable device suitable for transporting said mixing apparatus. In another aspect of the invention, said seed to be pregerminated and mixed with a phytoprotection product is transported by crane or forklift or hopper mechanism at each stage. Another mode of transportation contemplated in the invention of said seed at each or any stage of the method is by use of an auger.
By the term “phytoprotection product” is meant a material which provides an effective protection of rice seeds from pests' attacks. The invention is mainly directed to the protection of seeds and plants derived from such seeds from insect attacks, particularly rice water weevil, as well as from fungal attacks, in which cases the phytoprotection product comprises an insecticidally active compound
Klittich Carla Rasmussen
Redlich Michael Glenn
Burns Doane Swecker & Mathis L.L.P.
Pak John
Rhone-Poulenc Inc.
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