WO2014113001A1

WO2014113001A1 - Layered chemical treatment of stored crops

Info

Publication number: WO2014113001A1
Application number: PCT/US2013/021768
Authority: WO
Inventors: John Forsythe; James Zalewski
Original assignee: 1,4 Group, Inc.
Priority date: 2013-01-16
Filing date: 2013-01-16
Publication date: 2014-07-24

Abstract

Tuber storage facilities are treated sequentially with different sprout inhibition chemicals. Treatment of a facility with an aerosol of CIPC can be followed promptly with an aerosol of 1,4 DMN. The order of treatment may be reversed without significant overall affect upon the sprout inhibition efficacy of the sequential treatment.

Description

LAYERED CHEMICAL TREATMENT OF STORED CROPS

TECHNICAL FIELD

Methods and techniques for improving the storage ability of tubers and other root crops, such as potatoes.

BACKGROUND

Storage of potatoes and other types of tubers from fall harvest until spring has been commonplace in the agricultural industry. Such storage often requires the use of chemical sprout inhibitors to preclude sprouting of the potatoes. The principal chemical used has been chloroisopropyl carbamate (CIPC), which has been effective. However, it has often been overused and ineffectively utilized.

Additionally, it is a toxin and may have adverse environmental effects. Efforts have been underway, especially in European countries, to establish a Maximum Residue Limit (MRL) for CIPC on each individual potato as low as 10 ppm. Treatment of storage facilities solely with CIPC generally greatly exceeds such a limit. CIPC is generally applied to a storage facility as an aerosol.

Improvements in CIPC treatment technology have progressed over the past 20 years. For example, U.S. Patent No. 4,887,525 to Morgan discloses an improvement in aerosol distribution within a facility through use of a system that is capable of slowing circulation of the aerosol within the facility. CIPC is currently thermofogged to form minute liquid aerosol particles which crystallize upon evolving in the headspace of a storage facility to deposit upon stored potatoes as very fine crystals (solid particles) which sublimate to a vapor which inhibits sprouts as a mitosis inhibiting upon appearance of a nascent sprout (peep).

The commercial CIPC product available during the 1980s and early 1990s was known as 7A (78% by weight CIPC in 22% methanol). Although methanol was a very effective solvent, CIPC was typically deposited in large volumes on the fans and superstructure of the storage facility. Methanol did not efficiently dissolve or redistribute CIPC deposits throughout a storage facility. Practice of the reduced airflow in the storage facility, however, greatly diminished this unwanted, wasteful deposit. Later, in the mid 1990s, methods for creating useful aerosols from pure, molten CIPC that eliminates expensive, noxious solvents and their decomposition problems were described in U.S. Patent Nos. 5,935,660 and 6,068,888.

The uses of the low airflow technique and the molten CIPC technique have become standard in the U.S., with increasing use in the UK. Many other chemicals have been evaluated over the years as alternative sprout inhibitors to CIPC, including citral, 1 ,4-DMN (1 ,4 dimethyl naphthalene), and others.

The sprout inhibition properties of 1 ,4-DMN and its associated isomers (1 ,3-DMN and 1 ,6-DMN) have been known since about 1978. The 1 ,4-DMN isomer is naturally present in harvested potatoes in minute, but detectable quantities.

Since the 1990s, substantially pure 1 ,4-DMN has been marketed for the early treatment of stored potatoes under the name 1 ,4SIGHT® by the 1 ,4 Group,

Meridian, Idaho. See, e.g., U.S. Patent Nos. 5,965,489; 6,010,728; 6,310,004; and 6,375,999.

In 1997, a patent issued to Riggle et al. (U.S. Patent No. 5,622,912), asserting a synergistic effect between 1 ,4-DMN and CIPC when prepared as a premix, i.e., a composition of CIPC in 1 ,4-DMN. However, preferred aerosolization temperatures for CIPC and 1 ,4-DMN are significantly different. Thus,

aerosolization of a premix would be at a non-preferred temperature for at least one of the chemicals. The ratios set forth in Riggle et al. vary from 1 : 1 to 1 :4 CIPC to 1 ,4-DMN. Further, the minimum dosages used were 14 ppm of each chemical. Data in the Riggle et al. patent showed that treatment of the potatoes with 22 ppm CIPC was as effective as potatoes treated with a combination of CIPC and DMN at a total minimum of at least 28 ppm of combined sprout inhibitors. The potatoes treated by Riggle et al., had no prior treatments with any sprout inhibitors.

1 ,4-DMN has been used to treat potatoes early during storage. An advantage of 1 ,4-DMN is that it can be applied before suberization is completed and it may improve the suberization process. The action of 1 ,4-DMN is via a hormonal process, while CIPC is a mitosis inhibitor. Treatment with 1 ,4-DMN appears to extend dormancy. Typically, a first treatment with CIPC follows the first 1 ,4-DMN treatment many weeks or months later. This CIPC treatment occurs generally some one to four months after the potatoes have been stored, depending upon potato variety, soil and climate conditions during growth.

CIPC interferes with the suberization process, so treatment with CIPC is typically delayed until suberization is completed. Suberization of some potato varieties may require a delay of up to two months before treatment with CIPC. It is desirable to apply an aerosol of CIPC shortly thereafter, generally while the potatoes are dormant before sprouting occurs and before the potato pile has to compress.

DISCLOSURE OF THE INVENTION

A recent innovation has been the immediate sequential use of combinations of 1 ,4-DMN and CIPC.

In a particular embodiment, instead of a treatment merely with CIPC in mid- storage season, a "layered" treatment is conducted in which a treatment with CIPC is followed immediately, typically within about six hours, preferably within less than about two hours, by a treatment with 1 ,4-DMN, has provided surprising results in a variety of ways.

The term "layered" as used herein, shall mean treatment of stored crops with two different chemicals, such as when applied as aerosols, in a closely-timed sequence wherein one chemical typically exists in the headspace of a storage facility, where the second chemical is applied.

In the innovative layered treatment, excellent results are achieved when an aerosol of 1 ,4-DMN is introduced into a potato storage facility following treatment with an aerosol of CIPC.

The order of treatment may be reversed. However, it is generally preferred that the 1 ,4-DMN treatment immediately follow the CIPC aerosol.

A favorable feature of the "layered" treatment is that each chemical may be aerosolized at its preferred aerosolization temperature. Generally, for CIPC, especially as a molten feed, the thermofogging (aerosolizing) temperature can be from about 300°C (about 572°F) to about 400°C (about 752°F); the aerosolizing temperature for 1 ,4-DMN can be from about 200°C (about 392°F) to about 350°C (about 662°F). It is understood that individual compositions of CIPC or DMN can be applied at different aerosolization temperatures, depending on the particular formulations of excipients used. For example, CIPC in a methanol or clove oil or other solvent may be aerosolized at a slightly different temperature.

Aerosols of these chemicals can be created in thermofoggers, such as the combustion thermal fogging machine described and claimed in U.S. Patent

6,322,002, as well as in electrically heated thermofoggers.

Although an aerosol of 1,4-DMN is formed, it may exist as a vapor once it is in the storage facility because of its volatility. One of the surprising observed features of the "layered" treatment is that the 1 ,4-DMN aerosol or vapor can move the distribution of CIPC particles and droplets up through the potato pile to achieve a more uniform deposit of CIPC particles throughout the pile.

A typical aerosol of CIPC is introduced through ducts underneath the potato pile. Generally, the residual concentration of CIPC is very dense near the bottom of the pile and minimal near the top of the pile. Such an uneven distribution of CIPC particles often means that potatoes near the top of the pile will sprout prematurely, requiring another CIPC treatment, even though the potatoes at the bottom of the pile are not sprouting. Such excessive use of CIPC has brought criticism and regulatory restrictions from many sources. Also, residue samples determined for CIPC are done on potatoes taken from the top of the pile. Thus, if low residues are indicated, additional CIPC may be added even though the bulk of potatoes are not sprouting. An effort to address this problem is illustrated in U.S. Patent to Micka et al.

8,178,145 wherein sprout inhibitor is applied top-down as well as bottom-up to a potato storage pile. This technique has several deficiencies, such as the necessity of means to reverse airflow, which doesn't exist in all storage facilities, especially in UK and EU facilities. Also, this may provide adequate residues of CIPC for the top and bottom of the pile, but inadequate residues in the middle of the pile. Since sampling of residues from the middle of the pile is very difficult, such inadequate residues may result in undetected sprouting.

Excess use of CIPC, which unduly contaminates the stored potatoes, is an uneconomic use of the chemical and results in unnecessary quantities of CIPC in the wash water when the potatoes are washed upon removal from storage. Furthermore, in the UK and EU markets, maximum residue levels (MRLS) have been set, which mean that no potato in the pile may have more than a certain residue level of CIPC. Excess use of CIPC will cause many potatoes to exceed MRL standards.

The "layered" treatment, however, with the immediate introduction of an aerosol of 1 ,4-DMN following the CIPC aerosol, even when the 1 ,4-DMN is in vapor form in the potato storage facility (also moving up through the potato pile), has been demonstrated to redistribute the CIPC, causing a more even distribution of CIPC particles through the pile. This improved distribution effect was not expected and provides a more effective sprout inhibition than a typical CIPC treatment alone, regardless of the CIPC dosage. Such an effect avoids situations in which a large number of individual potatoes would exceed an MRL standard.

In the UK, for example, potatoes are often stored in large boxes. Circulation of CIPC throughout an individual box tends to be rather poor. The "layered" treatment has the capability to provide improved distribution of CIPC by following its aerosolization by treatment with an aerosol of 1 ,4-DMN per the protocols set forth herein. Particular care may be required, however, to ensure that the respective chemical aerosols permeate through the boxes and do not merely circulate around the boxes.

The dosage of CIPC applied is generally in the range of about 5 ppm to a full label rate of up to about 22 ppm. The selected dosage may be predetermined by examination of the potatoes. This is also true of the 1 ,4-DMN treatment, where the applied dosage may be from about 2 ppm to about 20 ppm. Generally, in contrast to the ratios set forth in Riggle et al., the "layered" treatment of the instant invention can apply CIPC at a generally higher quantity than the 1 ,4-DMN chemical. In preferred ratios, the DMN:CIPC ratios are from about 4:5, often about 8 ppm DMN to about 10 ppm CIPC to about 1 :4, for example, 5 ppm DMN to 20 ppm CIPC. However, variations in dosage rates are within the scope of the invention.

The "layered" treatment gives a longer lasting sprout inhibition effect than would be expected by the individual limited dosages of these two chemicals.

While not intending to be bound to any particular theory, recent evaluation of 1 ,4-DMN has revealed a particularly useful insight as to the effective results of the "layered" treatment. A potato sprouts first at its apical "eye" (i.e., the eye at the opposite end from the stem attachment). This phenomenon is known as apical dominance. It has been discovered that 1 ,4-DMN substantially diminishes apical dominance. This effect has also been observed for CIPC. Disruption of apical dominance allows substantially all eyes of a potato to sprout about the same time. Thus, a substantially even distribution of CIPC later will then prevent sprouting of substantially all the eyes at the same time.

This effect may result from the treatment of potatoes with 1 ,4-DMN immediately following a CIPC aerosol treatment, thereby causing this unexpected long-term sprout inhibition. One particular advantage of the "layered" treatment is to get improved sprout inhibition with smaller dosages of CIPC and providing durable uniform sprout inhibition.

It is also believed that 1,4-DMN can activate genes in the potato that had been previously determined to be associated with increased turgidity. CIPC is known to have no positive effect on turgidity. In fact, a pile of CIPC-treated potatoes will compress over time. A "layered treatment" can enhance turgidity to a pile of potatoes being treated substantially simultaneously with CIPC and 1 ,4-DMN. This effect has numerous benefits for preserving the treated potatoes in a healthy, non-sprouting condition. Such maintenance of turgidity keeps the pile from compressing, thereby allowing CIPC to be more evenly distributed throughout the pile upon initial aerosolization and upon later migration throughout the pile aided by the aerosol/vapor of 1 ,4-DMN. Additionally, potatoes which are more turgid are more desirable for sale and bring premium prices.

A non-compressed pile is further advantageous during ventilation that is usually done daily to maintain the desired storage temperature, typically about 5°C (42°F) to 10°C (50°F) and to sweep C0₂ from the pile. Potatoes respire, giving off C0₂ and water. C0₂ build-up is detrimental to the health and condition of the respiring potatoes. A non-compressed pile is more efficiently ventilated.

It is known that CIPC affects sprouts by its vapor. CIPC particles sublimate, producing a vapor that invades a nascent sprout, effectively inhibiting or suppressing it. A non-compressed pile allows the CIPC vapor to reach all the eyes in the potatoes, particularly if the potatoes have been treated to disrupt apical dominance.

Ventilation done at frequent intervals causes loss of both CIPC and

1 ,4-DMN over months of storage. Thus, an appropriate quantity of CIPC and 1,4-DMN is initially applied. The combination of these chemicals applied in the layered treatment effectively prevents further growth of the nascent sprouts so that subsequent loss of chemical via ventilation is not a problem because the eyes have been rendered non-viable by the layered treatment. In particular embodiments, all or most of the meristematic tissue in the eyes will have been killed, obviating the need for the continued presence of chemical sprout inhibitors. This is particularly true if apical dominance has been disrupted and the layered treatment is applied when nascent sprouts first express.

In contrast, CIPC applied alone in a conventional manner does not prevent pile compression and, consequently, additional treatments with CIPC are often ineffective because of pile compression, since many eyes may be shielded from being exposed to the additional CIPC. Generally, CIPC particles, or crystals, must be near to the "eye" to be effective. Thorough distribution of CIPC through a potato pile is important so that each potato eye is exposed, preferably, to multiple CIPC particles.

The "layered treatment," thus, has effects beyond what might be expected. It has been observed that where 1 ,4-DMN aerosol is promptly applied after a CIPC treatment, putting 1 ,4-DMN chemical through the same lines as the CIPC eliminates further cleanup of the aerosolization equipment. Also, CIPC deposits on fans, plenums, air ducts, and other building structures are removed or reduced by the subsequent treatment with 1 ,4-DMN, thereby conveying the CIPC to where it should be: in the pile of potatoes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a conventional treatment of a potato storage facility.

FIG. 2 shows a timeline of the treatment of a potato storage facility using a layered treatment according to a particular embodiment of the invention.

FIG. 3 shows a timeline of two layered treatments after the first treatment of 1 ,4-DMN according to an embodiment of the invention. MODE(S) FOR CARRYING OUT THE INVENTION

A conventional treatment of a potato storage facility is illustrated in FIG. 1. At Time A, usually within about ten days of the potatoes being introduced in the storage facility, the potatoes are treated with an aerosol of 1 ,4-DMN at a dosage of about 5 to 10 ppm. Later, at Time B, which is typically one to three months after the storage facility is filled, the storage facility is treated with an aerosol of CIPC at a dosage of about 20 ppm. At Time C, a further treatment with CIPC at a high dosage is typically required.

An improved protocol according to an embodiment of the invention is illustrated in FIG. 2, wherein the first two treatments at Time A' and Time B' are essentially the same as in FIG. 1. The improvement exists in using a "layered" treatment at Time C instead of a treatment solely with an aerosol of CIPC at a high dosage.

In a particular embodiment of the layered treatment, CIPC is applied at a dosage of from 5 to 10 ppm and 1 ,4-DMN is applied at about a similar dosage. Use of a layered treatment at Time C avoids overuse of CIPC and provides improved antisprouting effects. For example, a layered treatment using 10 ppm dosage of CIPC may result in a better distribution of CIPC within the potato pile and longer, more effective sprout inhibition than if the potatoes were treated solely with CIPC at a dosage of 20 ppm. Also, given the additional benefits of the coterminous

1 ,4-DMN treatment, the potatoes can stay in a more turgid, healthier condition.

A protocol according to another embodiment of the invention is illustrated in FIG. 3, wherein any treatment solely with CIPC is eliminated and a layered treatment is substituted in its place, i.e., at time B". Depending upon the potato variety, the condition of the potatoes at the time of storage and on the storage conditions, such a single layered treatment may provide optimum sprout inhibition and potato health for an entire storage season. If a single layered treatment is insufficient for this purpose, dual layered treatments may employ minimum dosages of CIPC and 1 ,4-DMN wherein less CIPC is used during a post-harvest season than if CIPC alone is used, even with a plurality of layered treatments.

Alternatively, a single layered treatment at some time period between B" and C" may be sufficient via the use of higher dosages of such chemicals. Such higher dosages may be between 10 and 15 ppm of each chemical. In particular

embodiments, the advantages of the layered treatment are obtained, especially when the second chemical applied in the layered treatment is 1 ,4-DMN.

EXAMPLE

A storage facility containing about 4000 tons of russet potatoes was treated first with an aerosol of CIPC at a dosage of about 10 ppm (applied dosage). The CIPC was in the form of molten pure CIPC derived from pure solid CIPC applied at a temperature of about 370°C (about 700°F) via a thermofogger.

Immediately after the CIPC was aerosolized and introduced into the storage facility, 1 ,4-DMN was introduced into the same thermofogger through the same tubing as the molten CIPC. The dosage was about 10 ppm (applied dosage). The thermofogger applied the 1 ,4-DMN aerosol at a fogging temperature of about 315°C (about 600°F).

Upon conclusion of the fogging of 1 ,4-DMN, the fogging equipment was observed to be clean and was shut down. The fans within the storage facility were free of any visible CIPC deposits. The fans continued to slowly circulate the aerosol/vapor of 1,4-DMN as well as sub-micron particles of CIPC that, via

Brownian movement, stay suspended for an extended period.

By having the fans continue to circulate the chemicals upward through the pile for an hour or more after the second aerosol treatment, the distribution of CIPC upward and throughout the pile can be continually improved.

After the storage facility remained closed to outward air for anywhere from about 24 to 48 hours, fresh air was introduced to sweep out built-up C0₂. Some loss of 1,4-DMN vapor and sub-micron particles of CIPC may have been lost during such ventilation. However, a substantial quantity of 1 ,4-DMN vapor will likely have been absorbed by the potatoes and most of the minute CIPC particles or crystals likely will be attached to the potatoes.

This "layered treatment" maintained the potatoes in a healthy, turgid, non- sprouting state for a period upwards of six months after a single layered treatment.

A similar storage facility treated at about the same time with only an aerosol of CIPC at an applied dosage of 18 to 20 ppm showed less turgidity and considerable more sprouting after six months than the facility treated by the "layered treatment."

In a particular embodiment, an especially useful protocol employs an early treatment with 1 ,4-DMN when the tubers (e.g., potatoes) are first put into storage. Unlike CIPC, 1 ,4-DMN does not interfere with suberization. Some evidence exists that 1 ,4-DMN may promote suberization and extend a dormant-like state of the stored potatoes maintaining the potatoes in a turgid condition and maintaining the potato pile in a substantially non-compressed condition. Apical dominance is disrupted by such DMN treatment.

Later, at a time when CIPC would normally be applied, a "layered treatment" is employed. As stated above, numerous advantages exist from such a "layered treatment," especially when applied to potatoes at the time "peeps" are first exhibited.

A range of dosages may be employed. The advantageous interaction of the chemicals in the "layered treatment" generally permits minimal dosages of each chemical to be used. Another advantage is providing a potential procedure to meet low MRL (maximum residue limit) being considered in many countries. The residue of CIPC on potatoes, especially ware (fresh) potatoes, has long been a concern. Such an MRL standard dictates that all potatoes must contain less than the MRL limit. The CIPC/1 ,4-DMN "layered treatment" has the potential to make such lower dosages of CIPC more effective for sprout suppression and general potato health than treatments solely with larger dosages of CIPC.

While 1,4-DMN is not on the GRAS list, it is a naturally occurring chemical found in harvested potatoes at detectable levels. Some theories exist that loss of 1 ,4-DMN in a potato is a possible cause of its breaking dormancy and that appropriate treatment with 1 ,4-DMN promptly after harvest can extend dormancy, which if not true dormancy, is a dormant-like state.

While the discussion regarding this "layered treatment" invention has focused on potatoes, it is effective for other root crops in storage such as sweet potatoes, yams, as well as other root vegetables, e.g., onions, sugar beets, and turnips. A further advantage of the layered treatment appears to be improved distribution of small particles/crystals on individual potatoes within the pile.

Examination of individual potatoes removed from the pile exhibit small CIPC particles/crystals densely distributed over the potato. The crystals/particles of CIPC appear to be at least partially embedded into the skin of the potato. Partial embedment of the CIPC crystals/particles may improve the long-term presence of the CIPC within the storage facility.

Partial embedment of small crystals/particles of CIPC may reduce the rate of sublimation during storage ventilation, thus preserving the CIPC for long-term sprout inhibition, especially when coupled with the diminishing affect of apical eye dominance by 1 ,4-DMN in the layered treatment or a prior treatment with 1 ,4-DMN or CIPC.

The instant invention is distinguishable from the techniques disclosed in the prior art in several significant ways. First, in the instant invention, the weight rates of CIPC to DMN can be greater than 1 : 1. Secondly, the instant invention does not involve mixtures of CIPC in DMN, such as those described in the '912 patent. Additionally, the '912 patent does not address advantages, a first CIPC treatment followed by a DMN treatment to improve CIPC distribution. Also, the '912 patent does not teach treating the potatoes when nascent sprouts appear or the advantages of previous treatments with 1 ,4-DMN or CIPC, or both in some spaced sequence.

In a particular embodiment, a CIPC treatment employs aerosolization of molten CIPC. An immediate use of the same thermofogger with 1 ,4-DMN can cleanse the thermofogger during aerosolization of the 1,4-DMN.

The layered treatment in one embodiment of the instant invention is very effective when performed before any significant sprouting occurs in a pile of harvested potatoes. Additionally, an appropriate dosage of 1 ,4-DMN can be applied to harvested potatoes shortly after storage is initiated. Such a treatment can maintain the potatoes in a turgid condition so that the pile does not unduly compress, which is a disadvantageous condition for a subsequent layered treatment. Such a treatment may be performed anywhere from two to six months after the initial storage of the harvested potatoes. An especially useful protocol for treating post-harvest potatoes includes devitalizing substantially all eyes of such potatoes and preventing future sprouting before said potatoes are processed or consumed. Such a protocol includes treating said potatoes with 1 ,4-DMN which promotes hydration maintenance, i.e., turgidity and extends a dormant-like state of the potatoes. This dormancy extension does not involve abscisic acid expression, which has been conventionally considered an indication of true natural dormancy and is a part of the evolution of a harvested potato before its eyes begin to sprout. The dormancy-like state induced by

1 ,4-DMN mimics true dormancy in that hydration is maintained and sprouting is delayed.

This first treatment with 1 ,4-DMN, or another chemical which induces a pseudo-dormant state is generally desirable. However, in some instances when the potatoes are in a healthy, substantially uninjured state and where the storage period is anticipated to be relatively short, this first step may be omitted. However, such treatment with 1 ,4-DMN or with another chemical which breaks the apical dominance of the eye located on a potato opposite to the stem attachment site is advantageous. The apical eye, when untreated, is the first to sprout and will naturally develop a substantial sprout before other eyes of the potato begin to "peep" or sprout.

Some embodiments of the present invention include breaking apical dominance. By doing so, substantially all eyes of substantially all the affected potatoes will begin to sprout at the same time and will develop in a substantially uniform manner. Thus, for post-harvest potatoes in a storage facility, disrupting apical dominance of substantially all stored potatoes may be achieved by treatment with a vapor or aerosol of a chemical such as 1 ,4-DMN and, optionally, CIPC or essential oils such as mint oil and the like. The applied dosage may be in the range of about 5 ppm to about 25 ppm with a residue (deposit) of about 2 ppm to 15 ppm being sufficient for the purpose of breaking apical dominance. CIPC has traditionally been applied as a sprout inhibitor at dosages of above 14 ppm and typically at 22 ppm and above. Conventionally, stored potatoes have been treated with aerosols of CIPC multiple times during a storage season and then treated with a dilute CIPC emulsion after the stored potatoes had been removed from storage and washed, in order to provide a consumer with a non-sprouting potato.

The instant invention achieves eye devitalization through a treatment regimen which has been sufficiently tested to establish reliable repeatability. An aspect of the invention involves treatment with smaller dosages of CIPC than typically used. An early treatment with 1 ,4-DM shortly after harvested potatoes have been stored is desirable to promote healing, turgidity and extend a

dormancy-like state so that when a later "layered treatment" is conducted, the potato pile is not unduly compressed so that aerosols of the sequentially applied chemicals can circulate freely within the potato pile. Further, the dosage of CIPC required in the "layered" treatment is typically much less than the label rate, an objective which has long been sought. Also, such "layered treatment" is conducted with "peeps" showing on substantially all eyes (the initial 1 ,4-DMN treatment breaks apical dominance) then substantially complete eye devitalization may be achieved. Very effective results are achieved when a reduced dosage of CIPC is applied between the initial 1 ,4-DMN aerosol treatment and the later layered treatment.

Utilization of the invention described herein, where an aerosol or vapor DMN is applied soon after a treatment CIPC achieves more uniform distribution of CIPC up through the pile so that potatoes receiving the least residue of sprout inhibitor are at the top of the pile so that sprouting, if it occurs, is readily observable so that additional sprout inhibitor may be applied, if necessary. Practice of this layered invention can provide a residue distribution wherein the residue in the middle of the pile is 75% to 90% of that in the bottom of the pile, while the residue of each chemical at the top of the pile is 50% to 75% of that at the bottom of the pile. Furthermore, when 1 ,4-DMN is applied as an aerosol immediately after an aerosol of CIPC, the 1 ,4-DMN can remove CIPC from the fans and the facility superstructure, and more effectively puts it to where it is intended; distributed within the potato pile. Thus, at a certain applied dosage of CIPC, a greater residue of CIPC can be deposited throughout the pile than when same dosage of CIPC is applied without a subsequent treatment with 1 ,4-DMN. Generally, the fan speed within the potato storage facility is adjusted to provide a low flow rate. A further embodiment of the instant invention may include a first aerosol treatment of CIPC distributed upward through the pile with a second aerosol treatment of 1 ,4-DMN upwardly through the pile, followed than by an aerosol treatment of CIPC directed downward through the pile with a follow-on aerosol treatment of 1 ,4-DMN flowing downward through the pile. The dosage of each aerosol treatment may be at a minimal predetermined level to achieve eye devitalization residues at each zone within the pile with greater average residues at the bottom and middle levels of the pile than at the top since sprouting is generally unobservable at the bottom and middle zones of a pile because undetected sprouting can be a very deleterious event.

In a particular embodiment where more than two chemicals are to be applied to a pile of stored potatoes, the aerosols of chemicals can be flowed upward through the pile in a greater quantity than the dosage of chemical or chemicals flowed downwardly through the pile.

While a four sequence treatment, such as that described above may be practiced, the proper protocol observed for a two-step sequence of the proper predetermined dosage of CIPC flowed slowly upward through the pile for an appropriate predetermined period of time followed by an appropriate predetermined dosage of 1 ,4-DMN flowed slowly upward through the pile for an appropriate predetermined period of time can provide an excellent graded distribution of both chemicals from bottom to top with each level having an appropriate residue for long term storage and beyond. This is especially the case of the treated storage facility is not ventilated between the separate treatments.

The embodiments described herein are not meant to limit the scope of the present invention. In each of the various embodiments, the methods, kits and system described herein disclose a way for collecting a sample and transporting the sample to another location for chemical residue analysis. However, the present invention may be carried out using embodiments different from those specifically described herein. Therefore, the scope of the present invention is not limited by the exemplary embodiments, but is defined by the appended claims.

Claims

What is claimed is: 1. A method of treating stored tubers with at least two different sprout inhibitors comprising:

treating the tubers with a predetermined dosage of CIPC in aerosol form; and treating the tubers with a predetermined dosage of 1 ,4-DMN in aerosol form

following the treatment of the tubers with CIPC, said 1 ,4-DMN aerosol applied while at least some aerosol of CIPC is extant among the tubers, said predetermined dosage of 1 ,4-DMN being less on a weight basis than said predetermined dosage of CIPC.

2. The method of claim 1 , wherein said aerosol of CIPC is thermally generated at an optimum aerosolization temperature for CIPC.

3. The method of claim 1 , wherein said aerosol of 1 ,4-DMN is thermally generated at an optimum aerosolization temperature for 1 ,4-DMN, wherein the optimum temperature for 1 ,4-DMN is substantially lower for 1 ,4-DMN than the optimum temperature for CIPC.

4. A layered treatment for treating non-dormant, stored potatoes containing a residue of a previously applied sprout inhibitor of CIPC and/or 1,4-DMN comprising:

a) applying an aerosol of CIPC at a dosage of from about 2 ppm to about 20 ppm to stored tubers; and

b) applying an aerosol of 1 ,4-DMN to said CIPC-treated potatoes at a dosage of from about 2 ppm to about 20 ppm, said 1 ,4-DMN application following substantially immediately upon completion of the CIPC treatment.

5. The treatment of claim 4, wherein said CIPC is applied as an aerosol generated via a thermofogger at a temperature of about 300°C (about 572°F) to about 500°C (about 950°F).

6. The treatment of claim 5, wherein said CIPC is substantially a pure molten CIPC introduced to a thermofogger.

7. The treatment of claim 5, wherein said 1 ,4-DMN is in an undiluted liquid form and is introduced through at least some of the same thermofogger lines as the CIPC chemicals.

8. The treatment of claim 4, wherein an aerosol of CIPC is present among the stored potatoes during introduction of an aerosol of 1 ,4-DMN to said potatoes.

9. A method of treating nascent sprouting stored potatoes, wherein an aerosol of CIPC is introduced into a potato storage facility while an aerosol of 1 ,4-DMN is present in said facility.

10. An aerosolization treatment of non-dormant potatoes in a box storagi potato facility, said potatoes containing a residue of a previously applied sprout inhibitor comprising:

a) treatment of the facility with an aerosol of CIPC at a dosage of from about 2 ppm to about 20 ppm; and

b) treatment of the facility with an aerosol of 1 ,4-DMN at a dosage of about 2 ppm to about 20 ppm, said treatment with 1 ,4-DMN following

substantially immediately after said CIPC treatment.

1 1. A method of treating post-harvest potatoes with sprout-inhibiting chemicals comprising:

a) treating the stored potatoes with an aerosol of 1 ,4-DMN while in the stored potatoes are in a dormant state; and

b) treating the potatoes while in a non-dormant state with a sequence of

sprout-inihibiting chemicals, wherein an aerosol of CIPC and an aerosol of 1 ,4-DMN are applied in close sequence to one another.

12. The method of claim 1 1 , wherein the 1 ,4-DMN is applied at a dosage of about 4 ppm to about 20 ppm.

13. The method of claim 1 1 , wherein the CIPC is applied at a dosage of about 2 ppm to about 20 ppm and said 1 ,4-DMN is applied at a dosage of about 2 ppm to about 20 ppm.

14. The method of claim 13, wherein the CIPC is applied at a dosage of about 4 ppm to about 12 ppm and the 1 ,4-DMN is applied at a dosage of about 4 ppm to about 10 ppm.

15. The method of claim 1 1 , wherein the first treatment with 1 ,4-DMN is applied before said stored potatoes have completed suberization.

16. The method of claim 1 1 , wherein the non-dormant stored potatoes are treated with an aerosol of CIPC following the treatment with 1 ,4-DMN.

17. A method of devitalizing eyes of post-harvest potatoes in a potato storage facility comprising:

Treating the potatoes with a first chemical capable of disrupting apical dominance prior to substantial emergence of sprouts on the potatoes.

applying a pair of chemicals separately after nascent sprouts are showing on at least some of the potatoes, one chemical being a mitosis inhibitor and the other chemical being a lower alkyl naphthalene, said pair of chemicals applied within about 48 hours of each other.

18. The method of claim 17 wherein said first chemical is CIPC or 1 ,4-DMN.

19. The method of claim 18 wherein said pair of chemicals are CIPC and 1 ,4-DMN.

20. The method of claim 17 wherein said pair of chemicals are applied separately without the potatoes being ventilated with fresh air in between said separate treatments.

21. The method of claim 17 wherein said first chemical is applied to said potatoes while substantially all potatoes remain in a state of dormancy.

22. The method of claim 21 wherein said first chemical is CIPC applied as an aerosol at applied dosage of less than about 20 ppm.

23. The method of claim 21 wherein the first chemical is 1 ,4-DMN applied as an aerosol at an applied dosage of less than about 20 ppm.

24. The method of claim 17 wherein the pair of chemicals are applied separately to have one chemical present in the headspace of said potato storage facility when the other chemical is applied.

25. The method of claim 24 where the pair of chemicals comprise CIPC applied as an aerosol and 1 ,4-DMN applied as an aerosol within less than about two hours following the CIPC treatment.