WO1992022205A1

WO1992022205A1 - Slug and snail repelling and/or killing composition

Info

Publication number: WO1992022205A1
Application number: PCT/AU1992/000270
Authority: WO
Inventors: Thomas John Rowland
Original assignee: Pellet Technology Australia Pty. Limited
Priority date: 1991-06-14
Filing date: 1992-06-09
Publication date: 1992-12-23
Also published as: EP0589976A4; EP0589976A1

Abstract

A composition for repelling and/or killing snails and slugs comprising an effective amount of a pyrethrin or a mixture of pyrethrins and a carrier. The pyrethrin is preferably in the form of the mark remaining after the solvent extraction of pyrethrins from the flowers of the pyrethrin containing plants. The carrier preferably comprises bran, or another food attractant for snails and slugs and ground rice hulls.

Description

Sluσ and Snail Repelling and/or Killing Composition Field of the Invention

The present invention relates to a slug and snail repelling and/or killing composition and more particularly to such a composition which may be produced from materials which would otherwise considered to be waste materials. Background of the Invention

Slugs and snails are a considerable pest to domestic gardeners and commercial plant growers. It is known to produce snail and slug killing compositions which are attractive to the animals and which poison them when eaten. Such slug and snail killers typically comprise a food material for the animal together with a molluscicidal composition which poisons the slugs and snails. The present inventor has realized that an effective slug and snail repelling and/or killing composition may be produced from materials typically considered not to have molluscicidal properties and which in preferred embodiments of the invention, are obtainable from waste residues of other processing operations. Disclosure of the Invention

The present invention consists in a slug and snail repelling and/or killing composition containing an effective amount of a pyrethrin or a mixture pyrethrins and a carrier therefor.

The pyrethrins are a family of naturally occurring insecticidal compositions found in the flowers of pyrethrum daisies such as Pyrethrum cinerariaefolium. In the recovery of the pyrethrum compounds the daisies are harvested, dried, ground and, normally, pelletized. The dried and pelleted material is then typically subjected to solvent extraction. The present inventor has found that the marc resulting from this solvent extraction process can be used very effectively in the production of compositions which repel and/or kill slugs and snails.

SUBSTITUTE SHEET The present invention is not limited to the use of pyrethrins contained in the marc. Natural or synthetic pyrethrins in purified or semi-purified form may be added to a suitable carrier to produce a slug and snail repelling and/or killing compositions according to the present invention. The use of the pyrethrin marc is preferred as it is a waste material typically having a low value.

The composition according to the invention preferably contains less than 0.1% by weight and preferably less than 0.01% by weight of pyrethrin. The pyrethrin could be present as a single compound but would be more likely to be a mixture of two or more of the individual compounds making up the pyrethrin family.

The marc is preferably mixed with a solid carrier which may be pelletized. This carrier preferably comprises a substantial proportion of waste materials such as ground rice hulls or straw. If the material is to be pelletized then it is desirable to include compositions which are known to facilitate pelletizing. A suitable material is rice bran which includes oils which accelerate pelleting speeds and bentonite which acts as a binder for the formed pellets. The bran also comprises a food attractant for molluscs and the composition preferably includes such an attractant. Other suitable attractants include flour and starch. Other binders which could be used in the pelleting process include naturally occurring ligno sulphonates.

If desired the super fine material resulting from the pelleting process may be used to form a dusting powder useful for the repelling and/or killing of slugs and snails.

It has been found that the composition according to the present invention is repellant to dogs and cats. This is an important advantage in slug and snail repelling and killing compositions as the conventional slug and snail killers are attractive to dogs and are also poisonous to them.

In a preferred embodiment the present invention comprises 10% of marc resulting from the solvent extraction of pelletized pyrethrum daisy meal and 90% of a carrier mixture. The marc contains less than half a percent of residual pyrethrins and is in material generally considered to be waste following the solvent extraction of the pyrethrins. The carrier mix preferably comprises 20% rice bran, 2% bentonite and 78% ground rice hulls, all of the foregoing percentages being percentages by weight. It has been found that when the above material is pelletized and the pellets sprinkled on a garden the garden is devoid of slugs and snails within a few hours of the application of the pellets. It was also found that plants in areas where the pellets had been spread did not show fresh slug and snail damage for a period of at least a few days after application of the pellets. It is not clear as to whether the slugs and snails are merely repelled by the composition according to this invention or whether they are actually killed by it. The inventor has noted that in an open garden situation snails in the area in which the composition according to the invention has been spread desist from eating plants and excrete large quantities of mucus. These molluscs tend to disappear quickly though it is not clear that they have died. Best Mode for Carrying out the Invention A composition according to the present invention by mixing together:-

(a) 10% by weight of a pyrethrin marc which was relatively finely ground but of a fibrous nature; this marc contained between 0.05 and 0.02% by weight of pyrethrins, and

(b) 90% by weight of a carrier material comprising (i) 78.5% by weight finely ground rice hills,

(ii) 1.5% bentonite, and

(iii) 20% by weight finely ground bran.

The composition was passed through a pellet mill to produce a pale brown coherent pellet. This material is hereinafter referred to as "Sluggo".

2. INTRODUCTION

One replicated small plot trial was conducted during September and October 1991 to evaluate SLUGGO for the control of snails in lettuce seedlings. The trial was conducted at the Agrisearch Services Pty Ltd office and laboratory at Orange, New South Wales, Australia.

This report contains the experimental methods used and presents the results obtained. 3. EXPERIMENTAL DETAILS

3.1 Trial Site Location

The trial was conducted at the Agrisearch Services Pty Ltd office and laboratory in Orange, New South Wales. An area 9 metres by 4 metres behind the laboratory was rotary hoed and prepared for the lettuce seedlings.

3.2 Target Pest

The target pest was the common garden snail Helix aspersa. The snails were collected from gardens in the city of Orange, New South Wales one day prior to use. Medium to large snails were used.

3.3 Test Plants

Lettuce seedlings, variety Imperial, were used. The seedlings had four to six leaves when planted out. All plots were watered lightly each morning during the trial period.

3.4 Treatment List

2 * Only half of the 1 m plots were treated. The treatments were applied once at commencement of the trial.

3.5 Formulation

SLUGGO - contains pyrethrin 25 mg/kg as the active ingredient in a bran based pellet with no colour. The formulation was as supplied by Pellet Technology Australia Pty Limited.

3.6 Trial Design

The trial was set up as a split plot design with the treatments as the main plots and "rainfall" as the sub-plots. "Rainfall" consisted of putting the treatments out on half the plots and watering them for two hours with a soaker hose. The total water applied was 35mm. The remaining plots were treated two hours after the

2

"rainfall". Each sub-plot was 1 m in area and contained six evenly spaced lettuce seedlings and two 17cm diameter plastic squat pots (one on the treated half and one on the untreated half of the sub-plot) . The total number of sub-plots was twenty four; four treatments by two moisture regimes by three replicates. the plot and sub-plot layout is described below.

Plot layout 1 m

W

1 m 1* 3 2*

1 3* 2

4 2* 3

4* 2 3*

3* 4 1*

3 4* 1

1 2* 4

1* 2 4*

* Simulated rainfall applied to pellets Treatments numbered 1-4 Sub-plot Layout 1 m

W

Treated Untreated

01 04

02 x 05 1 m

03 06

0 = lettuce seedling x = snails placed here = squat pots

Each of the sub-plots was enclosed with a black nylon shade cloth covered timber framed cage to prevent the snails from escaping.

3.7 Treatment Method

The treatments were applied evenly over half of each sub-plot around lettuce seedlings 1, 2 and 3. Seedlings 4, 5 and 6 were always on the untreated half of each plot.

3.8 Challenges and Assessments

All plots were challenged with fresh snails immediately after all treatments were applied and again at 6 and 13 days after treatment (DAT) .

Assessment of snail activity was made at 1 and 3 days after each challenge, ie. 1, 3, 7, 9, 14, and 16 DAT. Snails were assessed as active, knocked down, or dead.

The position of the snails was recorded as; on the harbourage, on the lettuce seedlings, on the cage, or on the ground. Whether they were on the treated half or the untreated half of the sub-plots was also recorded.

Individual lettuce seedling damage was rated using a 0-10 scale based on percentage leaf eaten (10 = completely eaten) . If seedlings were completely eaten then they were replaced for the next challenge. Seedlings were not replaced during a challenge.

Any phytotoxicity was recorded. 3.9 Statistical Analysis

From the number of snails active, knocked down, and dead data the percentage snails knocked down and dead was calculated. Analysis was only done to see if there was a difference in the efficacy of BAYSOL when "rainfall" was applied. To do this the data was transformed using SQRT(X+0.5) and analysed using a factorial analysis. Least significant differences (LSD) were calculated at the 5% level of probability to compare the means.

Lettuce plant damage data was transformed using SQRT(X+2) and analysed using a factorial analysis and LSD values calculated to compare means. 4. RESULTS AND DISCUSSION

The results are summarised in Tables 1-18. The results in full are presented in the Appendices. Means with common letters adjacent to them do not differ at the 5% level of probability. Data was transformed prior to analysis. See the Appendices for details.

Table 1 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 1 Day After 1st Challenge

Formulation

1. SLUGGO 2, SLUGGO 3, BAYSOL 4. Untreated Control

Mean

Table 2 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 3 Days After 1st Challenge

Table 3 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 1 Day After 2nd Challenge

Table 4 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 3 Days After 2nd Challenge

Table 5 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 1 Day After 3rd Challenge

Table 6 Summary of Results - Mean Percentage Snails Knocked Down and Dead at 3 Days After 3rd Challenge

Table 7 Summary of Results - Mean Lettuce Plant Damage Rating** 1 Day After 1st Challenge

Formulation Rate

Pellets/m''

1. SLUGGO 25

2. SLUGGO 50

3. BAYSOL 100

4. Untreated Control Mean

** Rating - 0 - no damage, 10 = totally eaten

Formulation Rate

Pellets/m'

1. SLUGGO 25

2. SLUGGO 50

3. BAYSOL 100

Rating - 0 = no damage, 10 = totally eaten

Table 9 Summary of Results - Mean Lettuce Plant Damage Rating** 1 Day After 2nd Challenge

Formulation

1. SLUGGO

2. SLUGGO

3. BAYSOL

4. Untreated Control Mean

** Rating - 0 = no damage, 10 = totally eaten

Table 10 Summary of Results - Mean Lettuce Plant Damage Rating** 3 Days After 2nd Challenge

Formulation

1. SLUGGO

2. SLUGGO

3. BAYSOL

4. Untreated Control

** Rating - 0 = no damage, 10 = totally eaten

Table 11 Summary of Results - Mean Lettuce Plant Damage Rating** 1 Day After 3rd Challenge

Formulation Rate

Pellets/m'

1. SLUGGO 25

2. SLUGGO 50

3. BAYSOL 100

4. Untreated Control Mean

** Rating - 0 = no damage, 10 = totally eaten

Table 12 Summary of Results - Mean Lettuce Plant Damage Rating** 3 Days After 3rd Challenge

Formulation

1. SLUGGO

2. SLUGGO

3. BAYSOL

4. Untreated Control

** Rating - 0 = no damage, 10 = totally eaten

Table 13

Summary of Results

Total Number of Snails at Each Position When Assessed 1 Day After 1st Challenge

Summary of Results

Total Number of Snails at Each Position When Assessed 3 Days After 1st Challenge

Table 15

Summary of Results

Total Number of Snails at Each Position When Assessed 1 Day After 2nd Challenge

Table 16 I

Summary of Results

Total Number of Snails at Each Position When Assessed 3 Days After 2nd Challenge

Table 17^"

Summary of Results

Total Number of Snails at Each Position When Assessed 1 Day After 3rd Challenge

Harbour Cage Ground

:ed Untreated Treated Untreated Treated Untreated 4 3 16 1

6 6

7 10

Table 18

Summary of Results

Total Number of Snails at Each Position When Assessed 3 Days After 3rd Challenge

Harbour Cage Ground

Treated Untreated Treated Untreated Treated Untreated

23 11 0 0 0 2

22 12 1 0 1 0

0 2 0 0 28 6

22 9 3 1 1 0

4.1 Lettuce Plant Damage

Although the SLUGGO pellets did not knockdown or kill the snails, the damage sustained by the lettuce seedlings in SLUGGO treated plots was statistically similar to that of seedlings in the BAYSOL treated plots, except at the 3 day assessment of the 2nd challenge. At that stage (six feeding days) a clear rate effect was observed with lettuce plant damage significantly higher in the plots treated^' ith the low rate of SLUGGO. Significantly less lettuce plant damage occurred in the plots treated with

BAYSOL compared with the plots treated with the high rate of SLUGGO. Damage was minimal to plants in the treated half of the high rate plots of SLUGGO compared to the damage to plants on the untreated half. That trend was evident at each assessment in the high rate of SLUGGO and to a lesser extent in the BAYSOL treated plots.

After six days of snail feeding on the SLUGGO pellets, no complete pellets remained in the plots. In plots treated at the low rate of SLUGGO there was the odd sign of bran flakes visible with flakes more prevalent in the plots treated at the higher rate. At all but two assessments, lettuce seedlings in the SLUGGO and BAYSOL treated plots had significantly less plant damage than the seedlings in the untreated plots. At the 1 day assessment of the 1st challenge, lettuce seedlings in the SLUGGO

2 treated plots at the high rate of 50 pellets/m had a similar mean lettuce plant damage rating to the untreated plots. This was due to one plant on the untreated half of one plot being almost totally consumed. The second time was at the 1 day assessment of the 3rd challenge when a cold night reduced snail feeding activity and low damage occurred in the untreated plots, hence similar damage to lettuce seedlings occurred in all treatment groups. The simulated rainfall after application of the pellets to half the plots had no effect on lettuce plant damage except at the 1 day assessment of the 2nd challenge. At that assessment there was significantly greater lettuce plant damage in the plots that received the "rainfall". 4.4 Snail Position Within Plots

In the SLUGGO treated plots snails were mainly found in the plastic squat pot harbourages. The majority of snails were on the harbourage in the treated half (southern side) of each plot. This may have been due to the snails appetite for the pellets and therefore they remained close to the pellets. The treated side was always the closest to the building nd so this may have influenced their aestivation habits.

Snails in the BAYSOL treated plots were found mainly on the ground as they were knocked down or dead. The majority were on the treated half (southern side) of the plots around the pellets.

The snails in the untreated plots were found mainly in the harbourages with some on the cage. Although no treatment was applied to the untreated plots, snails generally preferred the southern side of the plot. As previously mentioned, the proximity of the building may have had some effect. 4.3 Snail Control SLUGGO snail pellets did not knockdown or kill any snails during the three snail challenges. At the 3 day assessment of the 1st challenge it was noted that snail excreta in the SLUGGO plots was pellet coloured (observed in the harbourages on both treated and untreated halves of the plot) . Snails were consuming pellets and remaining active.

At the final assessment, 3 days after the 3rd challenge, none of the SLUGGO treated plots had pellets or broken down pellets visible but all BAYSOL treated plots had pellets visible. The BAYSOL treatment have good control of the snails with 97% knocked down or dead at the 3 day assessment of each of the three challenges. The lower percentage of snails knocked down and dead at the 1 day after the 3rd challenge assessment could have been due to the low overnight temperatures decreasing snail feeding activity.

"Rainfall" on the BAYSOL pellets immediately after application did not significantly effect the activity given against snails during the trial period. 5. CONCLUSIONS

5.1 Lettuce seedling damage was similar in the SLUGGO and BAYSOL treated plots with significantly greater damage in untreated control plots. The SLUGGO pellets were more desirable to snails than the lettuce seedlings. Seedling damage increased in the plots treated with the low rate of SLUGGO at the 3 day assessment of the 2nd challenge. The increased seedling damage may have been due to the low level of the alternative food source (SLUGGO) .

5.2 Lettuce seedlings within the treated half of the high rate of SLUGGO treatment had the least amount of damage of all the plots in both SLUGGO treatment groups.

5.3 The SLUGGO pellets were consumed by the snails as indicated by snail excreta which was pellet coloured (light brown) . 5.4 Snails in the SLUGGO treated plots tended to harbour on the plastic squat pots in each plot with the treated side (southern half) being favoured. Snails in the BAYSOL treated plots were found mainly on the ground as they were knocked down or dead. In the untreated plots snails were also in the squat pot harbourages provided and generally on the southern half of the plot (the half closest to the building) .

5.5 There was no sign of SLUGGO pellets at the final assessment and every BAYSOL treated plot had pellets visible. 5.6 SLUGGO snail pellets had no knock down activity against snails after three days exposure to pellets on three occasions; 0, 6, and 13 DAT. Fresh snails were used each time. 5.7 Good control of snails was given by BAYSOL at each challenge with 87% of snails either knocked down or dead at the three day assessment.

5.8 The simulated rainfall had little effect on the amount of seedling damage in the SLUGGO and BAYSOL treated plots and no effect on snail control.

5.9 No rainfall was recorded during the trial period and low overnight temperatures decreased the feeding activity of the snails during the 3rd challenge.

Claims

CLAIMS:

1. A slug and snail repelling and/or killing composition containing an effective amount of a pyrethrin or a mixture of pyrethrins and a carrier therefor.

2. A composition as claimed in claim 1 in which the composition contains less than 0.1% by weight of a pyrethrin or a mixture of pyrethrin.

3. A composition as claimed in claim 2 in which the composition contains less than 0.01% by weight of a pyrethrin or a mixture of pyrethrins.

4. A composition as claimed in claim 1 in which the pyrethrins are present in the composition as part of a marc resulting from the solvent extraction of pyrethrin from the flowers of pyrethrum daisies.

5. A composition as claimed in claim 4 in which the marc contains from 0.02 or 0.05% by weight of a pyrethrin or a mixture of pyrethrins.

6. A composition as claimed in claim 1 in which the carrier contains a food attractant for slugs and snails.

7. A composition as claimed in claim 6 in which the food attractant is selected from the group comprising bran, flour and starch.

8. A composition as claimed in claim 1 in which the carrier contains ground rice hulls.

9. A composition as claimed in claim 1 in which the composition comprises 10% by weight of pyrethrin marc containing from 0.02 ro 0.05% by weight of a pyrethrin of a mixture of pyrethrins, and 90% by weight of a carrier, the carrier comprising 78.5% by weight of finely ground rice hulls, 1.5% by weight bentonite and 20% by weight of rice bran. AMENDED CLAIMS

[received by the International Bureau on 15 October 1992 (15.10.92) original claims 1-9 replaced by amended claims 1-7 (1 page)]

1. A solid slug and snail repelling and/or killing composition containing a) a food attractant for slugs and snails; and b) less than 0.1% by weight of the composition of a pyrethrin or a mixture of pyrethrins.

2. A composition as claimed in claim 1 in which the composition contains less than 0.01% by weight of a pyrethrin or a mixture of pyrethrins. 3. A composition as claimed in claim 1 in which the pyrethrins are present in the composition as part of a marc resulting from the solvent extraction of pyrethrin from the flowers of pyrethrum daisies.

4. A composition as claimed in claim 3 in which the marc contains from 0.02 or 0.05% by weight of a pyrethrin or a mixture of pyrethrins.

5. A composition as claimed in claim 1 in which the food attractant is selected from the group comprising bran, flour and starch. 6. A composition as claimed in claim 1 in which the carrier contains ground rice hulls.

7. A composition as claimed in claim 1 in which the composition comprises 10% by weight of pyrethrin marc containing from 0.02 to 0.05% by weight of a pyrethrin or a mixture of pyrethrins, and 90% by weight of a carrier, the carrier comprising 78.5% by weight of finely ground rice hulls, 1.5% by weight bentonite and 20% by weight of rice bran.