Schedule P. Atmospheric and vacuum fumigation for the control of pests infesting packaged plant products

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This schedule covers a wide range of plant products, including grains, in packages such as bags (sacks), cartons, boxes and bales, which are permeable to the fumigants named. Bulk fumigation of certain agricultural and forest products is also included.

The success of the treatments given here will depend on the proper conduct of the procedures described in the text end on the provision of gas tight conditions in the structures employed. Adequate retention of fumigant must be checked by gas analysis; this is especially important in fumigation under sheets.

ATMOSPHERIC FUMIGATION CHAMBERS

All the fumigants named for the specific products may be used in specially designed and properly equipped atmospheric chambers as described in the text.

SHEETED FUMIGATIONS

At present most treatments under gas-proof sheets at atmospheric pressure are carried out with methyl bromide or phosphine and careful testing is required before other fumigants are used for treating specific materials.

OTHER STRUCTURES

Treatments under atmospheric pressure may be applied in a variety of structures, which can be rendered sufficiently gas tight, such as the holds of ships and barges, trucks, trailers, railway cars (wagons) and rooms in warehouses and other buildings. Methyl bromide and phosphine are mainly employed but HCN may be applied under certain conditions as described below. Other fumigants, such as the ethylene oxide/carbon dioxide mixture, have specialized applications.

VACUUM FUMIGATION

The operating pressure recommended for sustained vacuum fumigation, after the fumigant is introduced, is from 75 to 125 mm (3 to 5 in)of mercury. (This does not apply to the ethylene oxide/carbon dioxide mixture 1:9, which increases the pressure considerably.)

The pressure manipulations described in Chapter 9, which involve various alterations in the pressure of the chamber subsequent to the attainment of the initial vacuum, may be tested for different fumigants on different materials. No specific recommendations can be made before preliminary trials are made. The treatments given here are all for exposures under sustained vacuum.

CIRCULATION

Circulation of the fumigant in the space should be effected whenever possible. This may be done by fans or, in specially designed chambers, by means of recirculation systems. Circulation is necessary in vacuum fumigation - it is usually done for 15 min at the beginning of each hour of treatment. In atmospheric fumigation, circulation for at least 30 min at the beginning of the treatment is advisable (see text). In small-scale atmospheric fumigation of begged material, such as in railway cars or under small covers or tarpaulins, circulation may be omitted if adequate distribution of the fumigant is ensured by other means (see text).

PERMEABILITY OF PACKAGING MATERIALS

Many materials used for packaging are readily permeable to fumigants under the conditions recommended below. Phosphine diffuses readily, even at comparatively low temperatures. According to Roth and Richardson (1968) common brown (kraft) paper, glazed papers and corrugated cardboard are easily penetrated by methyl bromide; tar, laminated and wax papers, polyethylene films, masking tape and wallboard have comparatively low permeability to this fumigant.

A. Stored product pests in general

1. EMPTY BAGS MADE FROM JUTE (BURLAP) OR OTHER MATERIALS

(a) Loose, noncompressed bales or bundles

Methyl bromide. 15°C sod above: 24 to 32 g/m³ (24 to 32 oz/l 000 ft³ ) for 16 to 24 h under atmospheric pressure, or 40 g/m³ for 3 h under sustained vacuum. For control of Khapra beetle, Troqoderma qranarium Everts, the United States Department of Agriculture requires doubled dosage for vacuum fumigation and quadrupled dosage for atmospheric pressure treatment.

(b) Compressed bales

Methyl bromide. 15°C and above: 56 g/m³ for 4 h under sustained vacuum. Owing to high degree of sorption of vapours by material, care must be taken by operators to avoid inhalation of methyl bromide during unloading. After unloading, keep bales in wellventilated storage for at least 4 days.

2. PERMEABLE CARTONS, PACKAGES OR BAGS OF CEREALS

Containers should be tested for permeability. Heat-sealed cellophane polyethylene, wax paper or tar paper wrappings may not permit adequate penetration, even under vacuum fumigation.

(a) Methyl bromide

Under atmospheric pressure: 48g/m³ for 16 to 24 h at 10 to 14°C; 40g/m³ for 16 to 24 h at 15 to 20°C; 32g/m³ for 16 to 25 h at 21 to 25°C or 24g/m³ for 16 to 24 h at 25°C and above. Under sustained vacuum 40g/m³ for 3 h at 15°C and above.

(b) Hydrogen cyanide (HCN)

Under sustained vacuum: 2.5 g/m³ for 3 h at 20°C and above.

(c) Phosphine

At atmospheric pressure: sufficient of an aluminium or magnesium phosphide formulation to generate 1.5 9 of phosphine per m should be applied. Period of fumigation should be 7 days at 12 to 15°C, 6 days at 16 to 20°C, 5 days at 21 to 25°C or 4 days at 26°C or above.

(d) Ethylene dibromide (EDB)/methyl bromide mixture

At atmospheric pressure under tropical conditions: 16 to 32 g/m³ (16 to 32 oz/l 000 ft³ ) of 1:1 (w/w) mixture for 48 hours. At temperatures below 26°C 1:3 mixture of EDB to methyl bromide should be applied (Majumder and Muthu, 1964).

3. PERMEABLE CARTONS OR PACKAGES OF MILK POWDER

(a) Ethylene oxide/carbon dioxide mixture (1:9)

Suggested for vacuum fumigation at 720g/m³ for 3 h at 20°C and above. (See text for discussion of residues).

(b) Methyl bromide

Atmospheric pressure: see 2 (a) above.

(c) Phosphine

Dosage and exposure 2 (c) above.

4. PERMEABLE CARTONS OR OTHER CONTAINERS OF LOOSE RAISINS, CURRANTS, DATES, FIGS OR OTHER DRIED FRUIT

(a) Methyl bromide

Under atmospheric pressure: 24 g/m³ for 24 h at 15°C and above. Under sustained vacuum: 40 g/m³ at 15°C and above for 3 h. For lepidopterous pests, exposure in vacuum fumigation may be reduced to 2 h at temperatures above 20°C3. For fumigation under sheets or kraft paper over soil base, 32 g/m³ are recommended.

(b) Ethylene oxide/carbon dioxide mixture (1:9)

Under sustained vacuum: 640 g/m³ for 3 h at 20°C and above. (See text for discussion of residues.)

(c) Phosphine

At atmospheric pressure 1 9 phosphine per m³ of storage space.

5. PERMEABLE CARTONS OF DRIED FRUIT, INCLUDING DATES AND FIGS, IN COMPRESSED FORM

(a) Methyl bromide

Under sustained vacuum: 40 g/m³ for 3 h at 20°C and above.

(b) Ethylene oxide/carbon dioxide mixture (1:9)

Under sustained vacuum: 800 g/m³ for 4 h at 20°C and above. (See text for discussion of residues.)

(c) Phosphine

At atmospheric pressure see 4 (c) above.

6. PERMEABLE CONTAINERS OF FLOUR, MEALS, FEEDS, MIXED FEEDS AND MILLED CEREALS

(a) Methyl bromide

Under atmospheric pressure 48 g/m³ for 16 to 24 h at 10 to 14°C; 32 g/m³ for 16 to 24 h at 15 to 20°C;24 g/m³ for 16 to 24 h at 20 to 25°C or 16 g/m³ for 16 to 24 h at 25°C and above Under sustained vacuum: 48 g/m³ for 3 h at 20°C to 25°C; or 40 g/m³ for 3 h at 25°C and above. With flours, great care must be taken to avoid overdosage, which may be brought about through poor distribution of fumigant in a given load. To avoid this, fans or a recirculation system must be properly used.

Off-odours in bread and flour as a result of methyl bromide fumiqation have occasionally been reported (see full discussion in text).

(b) Phosphine

Under atmospheric pressure: Sufficient of an aluminium or magnesium phosphide formulation to generate 1.5 9 of Phosphine per m . Fumigate for 7 days at 12 to 15°C, 6 days at 16 to 20°C, 5 days at 21 to 25°C or 4 days at 26°C or above.

(c) Ethylene dibromide (EDB)/methyl bromide mixture

At atmospheric pressure under tropical conditions 32 to 48 g/m³ of 1:3 EDB:methyl bromide mixture w/w for 48 to 72 h (Majumder and Muthu, 1964).

(d) Ethylene oxide/carbon dioxide mixture (1:9)

Under sustained vacuum: 800g/m³ for 6 h at 25°C and over. (See text for discussion of residues.)

(e) Hydrogen cyanide (HCN)

Under sustained vacuum: 40g/m³ for 3 h at 20°C and over.

(f) Chloropicrin

Under atmospheric pressure: 32 to 48g/m³ for 24 h at 20°C and over. Higher dosages may be required for densely packed materials. This recommendation is subject to trial under local circumstances. Considerable time is required for ventilation.

7. BAGGED BARLEY, MAIZE, OATS, RICE, RYE, WHEAT AND OTHER GRAINS, ALSO DRIED BEANS, PEAS AND COCOA BEANS

(a) Methyl bromide

Under atmospheric pressure 40g/m³ for 16 to 24 h at 4 to 9°C; 32g/m³ for 16 to 24 h at 10 to 14°C; 24g/m³ for 16 to 24 h at 15 to 20°C or 16g/m³ for 16 to 24 h at 21°C and above. Under sustained vacuum. 56g/m³ for 3 h at 4 to 9°C; 48g/m³ for 3 h at 10 to 14°C; 40g/m³ for 3 h at 15 to 20°C; or 32g/m³ for 3 h at 21°C and above.

(b) Phosphine

Under atmospheric pressure: Sufficient of an aluminium or Magnesium phosphide formulation to generate 1.5 9 of phosphine per m . Fumi gate for 7 days at 12 to 15°C, 6 days at 16 to 20°C, 5 days at 21 to 25°C or 4 days at 26°C or above (Heseltine and Thompson, 1957; Harada, 1962; Hubert,1962; Pingale et al, 1963; Cogburn and Tilton, 1963; Rai et al, 1962; Lochner, (1964a).

(c) Ethylene dibromide (EDB)/methyl bromide mixture

Under tropical conditions at atmospheric pressure: use treatments given in 2 (d) above.

(d) Hydrogen cyanide (HCN)

Under atmospheric pressure: 32g/m³ for 24 h at 20°C and above. Under sustained vacuum: 40g/m³ for 3 h at 20°C and above. For rice, see Redlinger (1957c).

(e) Chloropicrin

Under atmospheric pressure: 48g/m³ for 24 h at 20°C and above.

(f) Ethylene dichloride/carbon tetrachloride mixture (3:1)

Under atmospheric pressure: 480g/m³ for 24 h at 20°C and above; or 360 g/m for 48 h at 20°C and above.

(g) Ethylene dibromide

Under atmospheric pressure: 75g/m³ for 24 h at 25°C and above. Suggested from work in India for use under tarpaulins at 240 9/1 000 bags (Pingale and Swaminathan, 1954). See discussion in text.

8. NUTS, SHELLED (NUTMEATS) OR IN THE SHELL: ALMONDS, BRAZIL NUTS, BUTTERNUTS, CASHEW NUTS, CHESTNUTS, FILBERTS (HAZELNUTS), HICKORY NUTS, PECANS, GROUNDNUTS, PISTACHIO NUTS AND WALNUTS.

(a) Methyl bromide

Under atmospheric pressure 48g/m³ for 16 to 24 h at 4 to 9°C; 49 g/m for 16 to 24 h at 10 to 14 C; 32g/m³ for 16 to 24 h at 15 to 20°C; 24g/m³ for 16 to 24 h at 21 to 25°C or 16 to 24g/m³ for 16 to 24 h at 25°C and above. Under sustained vacuum: 56g/m³ for 3 h at 4 to 9°C; 48g/m³ for 3 h at 10 to 14°C; 40g/m³ for 3 h at 15 to 20°C; 32g/m³ for 3 h at 21 to 25°C; or 24g/m³ for 3 h at 25°C and above. With lepidopterous pests, exposure in vacuum fumigation may be reduced to 1.5 or 2 h when the temperature is 20°C or above.

(b) Hydrogen cyanide (HCN)

Under atmospheric pressure: 32g/m³ for 24 h at 20°C and above. Under sustained vacuum: 40g/m³ for 3 h at 20°C and above.

(c) Chloropicrin

Under atmospheric pressure: 48g/m³ for 24 h at 20°C and above. Very thorough aeration required.

(d) Ethylene oxide/carbon dioxide mixture (1:9)

Under sustained vacuum: 560 to 640g/m³ for 3 h at 20°C and above. Use the higher dosage for nuts in shells and for nuts packed in cartons. (See text for discussion of residues.)

(e) Ethylene dichloride/carbon tetrachloride mixture (3:1)

Under atmospheric pressure: 400g/m³ for 48 h at 20°C and above; or 640 g/m for 24 h at 20°C and above. Recommended for wellconstructed fumigation chambers only.

(f) Phosphine

Under atmospheric pressure: Sufficient of an aluminium or magnesium phosphide formulation to generate 1.5 9 of phosphine per m3.

9. SPICES OF ALL KINDS

(a) Methyl bromide

Under atmospheric pressure: 16 to 24g/m³ for 16 to 24 h at 20°C and above. Under sustained vacuum: 40g/m³ for 3 h at 20°C and above. Treatment at lower temperatures may be practicable, following the schedule for cereals.

(b) Hydrogen cyanide (HCN)

Under atmospheric pressure: 24 to 32g/m³ for 24 h at 20°C and above. Under sustained vacuum 40 g/m for 3 h at 20°C and above.

(c) Phosphine

Under atmospheric pressure: Sufficient of an aluminium or Magnesium phosphide formulation to generate 1.5 9 of phosphine per m . Fumigate for 7 days at 12 to 15°C, 6 days at 16 to 20°C, 5 days at 21 to 25°C or 4 days at 26°C or above.

(d) Ethylene dibromide (EDB)/methyl bromide mixture

Under tropical conditions at atmospheric pressure; use schedule given in 2 (d) above.

(e) Ethylene oxide/carbon dioxide mixture (1:9)

Under sustained vacuum: 640g/m³ for 3 h at 20°C and above.

B. Golden nematode (Heterodera rostochiensis), in loose or compressed bales or bags made from jute (burlap) or other materials

Methyl bromide

Under atmospheric pressure: 368g/m³ for 16 h at 10°C and above. Atmospheric fumigation only effective for loose bales or bundles (Lear and Mai, 1952).

United States Department of Agriculture (USDA, 1976) only lists sustained vacuum treatments as follows:

Methyl bromide in 26 in vac (100 mm abs. press.); 128g/m³ for 16 h at 4 C and above; 168g/m³ for 12 h at 4°C and above; 256g/m³ for 8 h at 4°C and above; add 32 9 and 2 h at -1 to 4°C, add 48 9 and 4 h at -7 to 2OC; add 48 9 and 6 h at -12 to -8OC.

C. European Corn Borer (0strinia nubilalis), species of Sesamia and other lepidopterous borers in nonperishable products

Also a wide variety of agricultural pests which may enter the following materials incidentally or for hibernation (Monro, 1947b): broom corn and maize stalks in bales or bundles (stalks and panicles of Sorqhum vuluare var. technicum or stalks of Zea mays or related plants).

(a) Methyl bromide

Under atmospheric pressure: 112g/m³ for 16 h at 5 to 9°C; 80g/m³ for 16 h at 10 to 14°C or 40g/m³ for 16 h at 15°C and above. Under sustained vacuum: 96g/m³ for 2.5 h at 0 to 4°C; 80g/m³ for 2.5 h at 5 to 9°C; 64g/m³ for 2.5 h at 10 to 14°C; or 40g/m³ for 2.5 h at 15°C and above.

(b) Hydrogen cyanide (HCN)

Under sustained vacuum 48g/m³ for 3 h at 15°C and above.

D. Pink Bollworm, Pectinophora qossypiella, and other insects infesting cotton

1. COTTON IN BALES, LOOSE OR HYDRAULICALLY PRESSED

Hydrogen cyanide (HCN)

Under sustained vacuum: 40g/m³ for 2 h at 15°C and above. U.S. Department of Agriculture Regulation HB-164 (March 1923) stipulates that after the introduction of the fumigant into the evacuated chamber, the pressure in the chamber be raised to 125 mm (5 in) of mercury by the introduction of air; and that the pressure be kept at this level until the end of the 2-hour exposure.

2. COTTONSEED BAGGED OR PACKAGED

Methyl bromide

Under atmospheric pressure: 64g/m³ for 24 h at 4 - 15°C or 48g/m³ for 24 h above 15°C. Under sustained vacuum: 64g/m³ for 2 h at 4°C and above (load limit 50 percent of chamber volume).

Hvdroqan cyanide (HCN)

Under vacuum, 100 mm absolute pressure: 60g/m³ for 2 h at 4°C or above (load limit 50 percent of chamber volume).

Phosphine

Sufficient of an aluminium or magnesium phosphide formulation to generate 2 9 of phosphine per m ; for 5 to 7 days at 10°C or above.

3. EXTERNAL FUMIGATION OF COTTON BALES

The Government of India requires that all bales of American cotton entering that country should be subjected to atmospheric fumigation with hydrogen cyanide to control the boll weevil (Anthonomus qrandis Bob.) or other insects which may be found on or near to the surface of the bales (Liston, 1920; Liston and Gore, 1923; Turner and Sen, 1928).

E. Hay, baled, including Lucerne (Alfalfa) hay

ALFALFA WEEVIL, Hypera postica (Gyll.)

Methyl bromide

Under atmospheric pressure: 32g/m³ for 16 to 24 h at 15°C and above. Under sustained vacuum: 40g/m³ for 3 h at 15°C and above. Vacuum fumigation probably not economically feasible.

2. CEREAL LEAF BEETLE, Oulema melanopus (Kirby)

United States and Canada: Department of Agriculture schedules. Methyl bromide

F. Cigarette Beetle, Lasioderma serricorne, (F.) and Tobacco Moth, Ephestia elutella (Hbn)

1. ALL TYPES OF CIGARETTE TOBACCO

With these types in hogsheads and bales, atmospheric pressure cannot be relied upon for complete mortality, even with very long exposure periods, except with the fumigant phosphine. Vacuum fumigation using other fumigants is effective with bales, hogsheads and most packages (Tenhet, 1957).

(a) Hydroqen cyanide (HCN)

Under atmospheric pressure: 24g/m³ for 48 to 72 h at 7 to 20°C; or 16g/m³ for 48 to 72 h at 21°C and abOve. Under sustained vacuum: 84g/m³ for 4 h at 7 to 20°C; or 64g/m³ for 4 h at 21°C and above.

(b) Methyl bromide

Under atmospheric pressure: 32g/m³ for 48 to 72 h at 7 to 20°C; or 20g/m³ for 48 to 72 h at 21°C and above. Under sustained vacuum: 80g/m³ for 4 h at 7 to 20°C; or 64g/m³ for 4 h at 21°C and above.

(c) Acrylonitrile/carbon tetrachloride (1:2)

Under atmospheric pressure: 56 to 80g/m³ for 48 to 72 h at 7 to 20°C or 48 to 64g/m³ for 48 to 72 h at 21°C and above. under sustained vacuum: 80g/m³ for 4 h at 7 to 20°C; or 64g/m³ for 4 h at 21°C and above.

(d) Phosphine

Sufficient of an aluminium or magnesium phosphide formulation to generate 0.67 to 1 9 of phosphine per m .

2. CIGARS AND CIGAR TOBACCOS, EXCEPT CIGARS WRAPPED IN BALES

Vacuum fumigation effective for boxes of cellophaned cigars and sealed cartons of boxes of cigars. Impractical to fumigate satisfactorily boxes of cigars overwrapped in cellophane (Tenhet, 1957). Methyl bromide not recommended for cigar tobaccos because off-odour sometimes results.

(a) Hydroqen cyanide (HCN)

Under atmospheric pressure: 24g/m³ for 48 to 72 h at 7 to 20°C; or 16g/m³ for 48 to 72 h at 21°C and above Under sustained vacuum: 80g/m³ for 4 h at 7 to 20°C; or 64g/m³ for 4 h at 21°C and above.

(b) Acrvionitrile/carbon tetrachloride (1:2)

Under atmospheric pressure: 56 to 80g/m³ for 48 to 72 h at 7 to 20°C or 64 to 80g/m³ for 48 to 72 h at 21°C and above. Under sustained vacuum: 80g/m³ for 4 h at 7 to 20°C; or 64g/m³ for 4 h at 21°C and above.

(c) Ethylene oxide/carbon dioxide (1:9)

Under sustained vacuum: 960g/m³ for 4 h at 21°C and above.

3. CIGARS WRAPPED IN BALES

(a) Hydrogen cyanide (HCN)

Under atmospheric pressure: 24g/m³ for 48 to 72 h at 21°C and above. Under sustained vacuum: 80g/m³ for 4 h at 21°C and above.

(b) Acrvionitrile/carbon tetrachloride (1:2)

Under atmospheric pressure: 64 to 80g/m³ for 48 to 72 h at 21°C and above. Under sustained vacuum: 80g/m³ for 4 h at 21°C and above.

(c) Ethylene oxide/carbon dioxide (1:9)

Under sustained vacuum: 1 040g/m³ for 4 h at 21°C and above.

G. Wood-boring beetles and wood wasps in timber cut in board lengths

Methyl bromide

Under atmospheric pressure: 32g/m³ for 24 to 36 h at 15°C and above. Fumigation may be carried out under gas-proof sheets and in the holds of ships (Burden and McMullen, 1951). Good distribution of fumigant is essential. Vacuum fumigation probably not economicaliv feasible.

H. Mangolds

Methyl bromide

Fumigation of mangolds in clamps (piles) to control aphid vectors of virus yellows (Dunning et al 1962). Methyl bromide under gas-proof sheet for a minimum of 3 h to effect a c x t product 100 mg in/l.

I. General references to plant product treatments

Treatments

USDA (1976, 1977 and updated revisions).

Residues

Lindgren et al (1968).

Schedule Q. Fumigation of mills, empty structures and tobacco warehouses

Mills and empty structures that may be made sufficiently gas tight for atmospheric fumigation, including warehouses, empty holds of ships and other carriers (for treatment of most structures containing goods, see Schedule P).

1. SEALED BUILDINGS (MILLS, EMPTY WAREHOUSES AND SIMILAR BUILDINGS)

For eradication of residual populations of stored product insects and similar pests.

(a) Methyl bromide

40 to 48g/m³ for 24 h at O to 4°C; 32 to 40g/m³ for 24 h at 5 to 9°C; 24 to 32g/m³ for 24 h at 10 to 14°C; or 16 to 24g/m³ for 24 h at 15°C and above. Vary dosage according to gas tightness O3f building. Also use lower dosage for larger spaces over 14 000 m³ (500 000ft³). The use of a procedure for gas analysis, e.g. thermal conductivity analyser, is recommended so that c x t products can be determined and the required treatment conditions assured.

(b) Hydroqen cyanide (HCN)

8 to 12g/m³ for 24 h at 15°C and above. If building is thoroughly cleaned inside to remove accumulations of debris, a lower dosage may be used.

(c) Chloropicrin

16g/m³ for 24 h at 15°C and above. In view of strong tear gas effect it is not recommended for large structures. It may be atomized at lower temperatures by aerosols (see text).

(d) Dichlorvos (DDVP)

Dichlorvos vapour applied with treatments given below is effective against insects moving freely on surfaces or in the free space of closed structures, but it does not penetrate effectively into deep cracks and crevices (see text for full discussion).

Tobacco warehouses. Dispensed more conveniently as an aerosol, but may be applied as a spray.

Cigarette beetle, Lasioderma serricorne (F.):71 mg/m³ (2 9/l 000 ft³ ) twice a week (Tenhet et al, 1958; Childs, et al, 1966). An effective programme for year-round control of this insect is one HCN fumigation per year at 48g/m³ (48 oz/l 000 ft³ ) for 72 h together with dichlorvos 71 mg/m³ (2 9/1 000 ft³ ) twice a week (Childs, 1967).

Tobacco moth, Ephestia elutella (Hbn.): 35 mg/m³ (1 g/l 000 ft³) per week (Press and Childs, 1966).

Stored-product insects qeneraliy. In warehouses, mills and other structures, dichlorvos in vapour form is effective against some of these insects (Attfield and Webster, 1966). Use in the presence of foodstuffs would be contingent upon official government approval for residue tolerances and public safety.

Houses, aeroplanes and buildings qaneraly. For public health. Control of flies, mosquitoes, cockroaches, bedbugs, etc.

Dichlorvos dispensed from aerosols or sprays or volatilized from resin strips is now widely used in this field. The literature is extensive. Consult manufacturers' recommendations and regulations of of official public health agencies. A comprehensive summary on dichlorvos is given by Attfield and Webster (1966).

N.B. Vapour saturation of dichlorvos occurs at low concentrations. See Table "Properties of dichlorvos" in text.

2. BUILDINGS UNDER GAS PROOF SHEETS

For eradication of residual populations of stored product insects and similar pests.

Methyl bromide

80g/m³ for 24 to 36 h at 0 to 4°C;72g/m³ for 24 to 36 h at 5 to 9°C;64g/m³ for 24 to 36 h at 10 to 14°C or 56g/m³ for 24 to 36 h at 15°C and above. Use of thermal conductivity analyser recommended to check concentrations so that a certain predetermined c x t product may be attained (see text). Additional dosage required for beetles of Troqoderma sp., see Armitage (1956, 1958).

3. HOUSES AND BUILDINGS UNDER GAS PROOF SHEETS OR PROPERLY SEALED AT ALL OUTSIDE POINTS

For dry wood termites (Kalotermes spp.) and other structural woodinfesting insects. Coleopterous families Anobiidae, Lyctidae, Bostrichidae, Buprestidae, Cerambycidae, Scolytidae, etc. Hymenopterous species also, including carpenter ants and wood wasps.

(a) Methyl bromide

64g/m³ for 16 to 24 h at 10 to 14°C; or 48g/m³ for 16 to 24 h at 15°C and above. Exposure period may be reduced at temperatures above 20°C. Use of thermal conductivity analyser recommended.

(b) Hydrogen cyanide (HCN)

40g/m³ for 48 h at 10°C and above. Ensure that electrical sparks or pilot flames do not start fire or explosion when high concentrations are localized at start of fumigation.

(c) Sulphuryl fluoride

32g/m³ for 24 h at 10 to 20°C; or 16g/m³ for 24 h at 20°C and above. The manufacturer of sulphuryl fluoride provides a special chart (Fumiguide) which, when used in conjunction with a thermal conductivity analyses or other gas analysis technique ensures that fumigant concentrations are being maintained at the desired level (Stewart, 1966).

(d) Acrylonitrile/methylene chloride mixture

This mixture (34 to 66 by volume) has been tested successfully in Florida for dry wood termite control in buildings (Young, 1967). Suggested dosage 64 to 96g/m³ for 24 h at temperatures above 15°C.

4. EMPTY CARGO SPACES IN SHIPS, EMPTY RAILWAY CARS, ETC.

For residual populations of insects. Proper aeration of cargo spaces in ships after fumigation most important (see text) (Monro, 1969; Monro et al, 1952).

(a) Hydrogen cyanide (HCN)

12g/m³ for 10 to 12 h at 0 to 4°C; 10g/m³ for 10 to 12 h at 5 to 9°C or 8g/m³ for 10 to 12 h at 10°C and above.

(b) Methyl bromide

32g/m³ for 10 to 12 h at 0 to 4°C; 24g/m³ for 10 to 12 h at 5 to 9°C or 16g/m³ for 10 to 12 h at 10°C and above.

Multiply this schedule by 6 for Khapra beetle, Tronoderma qranarium Everts, which is difficult to kill with methyl bromide.

5. SNAILS IN CARGO SPACES AND ON CARGO - See schedule T.

Schedule R. Local (spot) fumigants for mills

Representative formulations (all parts by volume)

Acrylonitrile 1 : carbon tetrachloride 2
Ethylene dibromide 1 : ethylene dichloride 1 : carbon tetrachloride 3
Ethylene dichloride 3 : carbon tetrachloride 1 (use twice dosage recommended below)
Chloropicrin alone (for most purposes, use 75 percent of dosage recommended below)
Ethylene dibromide 7 : methyl dibromide 3 (weight to weight) (use 33 percent of dosage recommended below).

See Chapter 7 for discussion of fumigant mixtures.

Fumigation should normally only be done when the building is empty of people other than properly trained fumigators (nights, holidays or weekends).

Exposure period 16 to 24 hours

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