CONTROL OF ORCHARD AND GARDEN PESTS AND DISEASES.

New Zealand Journal of Agriculture, Volume XXX, Issue 1, 20 January 1925, Page 44

CONTROL OF ORCHARD AND GARDEN PESTS AND DISEASES.

Horticulture Division. It is important to distinguish between the different pests and diseases that attack fruit-trees, otherwise a great deal of time and material will be. wasted in useless attempts to control them by the' application of wrong spraying-mixtures.. If the nature of the disease is known the remedy is more easily determined. It may therefore be of value to here place the principal diseases in their respective classes, and likewise the spraying-materials most generally in use in a corresponding. class. These can be used for reference when considering the methods of control. Pests. “ Controls. Chewing-insects .. . . . . Poison sprays. • Sucking-insects .. . . . ■ . .v "Contact sprays (insecticides). ■ Diseases. Fungoid diseases .'. .. . . Fungicides. \ ' CHEWING-INSECTS. Chewing-insects comprise those that chew and eat their food, whether it be leaf or fruit. The following are the most common and destructive Codlin-moth, leaf-roller caterpillar, pear-slug, bronze - beetle, raspberry-bud weevil, tomato-caterpillar. , POISON SPRAYS. . - ■ . Arsenate of lead is now almost universally used, and answers practically all purposes. Use ijlb. of arsenate - of - lead paste or % lb. of powder to 50 gallons of water (2 oz. paste, or .1 oz. powder to 4 gallons water). In the case of pip-fruits commence spraying as soon .as the majority of the petals have fallen, and repeat the application at intervals of fourteen to twenty-one days throughout the season, the main object being to keep the fruit and foliage thoroughly covered with the spray. Applications to late . varieties of apples are often discontinued too soon, and the crop is packed while infected with leaf-roller caterpillar, with great resultant loss. .... SUCKING-INSECTS. . - Sucking-insects comprise those that feed upon the juices of the fruit, stem, and foliage by means of a proboscis which penetrates the surface and sucks up the natural juices of the plant. The following are the principal orchard insects in this, class : Mussel, San Jose and other scale insects, mealy , bug, woolly aphis and other aphides, red mite, pear-mite, thrips, and leaf-hoppers. INSECTICIDES (CONTACT SPRAYS). Red-oil emulsion has proved most effectual for these pests , on fruittrees. There are numerous brands of commercially-prepared oils on

the market, needing only the addition of soft water to make them ready for use. They are quite easy to mix if the following instructions are carried out : Take one part of red oil and place it in a bucket (a benzine-tin answers admirably). Next take one part water and pour this into the vessel containing- the oil. Stir or agitate the mixture, and an emulsion- is readily formed. It is then ready for further dilution as may be required. Should the water be very hard a little soda should be dissolved in it before mixing. The following strengths ■ are recommended, but may vary slightly according to the locality and time of application : — Pip-fruits. i gallon red oil to 10-15 gallons water, applied towards the end of August or the beginning of September. Trees badly affected with woolly aphis may be sprayed with red oil, 1-60, as soon as the fruit is gathered. Stone-fruits— gallon oil to 12 or 15 gallons water, in early spring, but when the trees are dormant. Trees affected with San Jose scale in autumn should be cleaned up with lime-sulphur sprays before they become dormant. Citrus-fruits. — 1 gallon oil to 40 gallons water. Apply in spring, after an inch or so of growth has been made ; also in autumn, towards the end of March, when the summer crop has been gathered. ' • Nicotine Concentrate (Black Leaf 40). — This is a safe and efficient insecticide for use during the growing-period. Use one part of Black Leaf 40 to 1,200 parts of water, first adding 3 lb. or 4 lb. of dissolved soap to the 100 gallons water. The soap is an important ingredient, but when using ■ Black Leaf 40 . in combination with other sprays the soap should be omitted. Lime - sulphur Concentrate. —-This mixture has some insecticidal qualities ; they are chiefly useful in the control of red mite and San Jose scale. For details of strength of mixture see “ Fungicides.” : FUNGOID DISEASES. Following are some of the principal fungoid diseases: Black-spot on apple and pear, leaf-curl on peaches and nectarines, bladder or pocket plums on plums, powdery mildew on apples, shot-hole fungus on apricots, brown-rot of stone-fruits, and verrucosis of citrus-fruits. fungicide's. There are three in general use : — (1.) Bordeaux Mixture. — In this the active agent is bluestone (sulphate of copper) temporarily neutralized by combination with quicklime, both being dissolved in water. In recipes the ingredients are quoted in this order. The right method of mixing these ingredients is most important and should be carefully followed. To make bordeaux, 8-6-50, dissolve 8 lb. bluestone in 25 gallons water. •; This may be done by placing the bluestone in sacking and suspending it in the water. Take 6 lb. of good quicklime and slake it in another barrel, -using a small quantity of water ; then dilute it up to 25 gallons. Pour the two solutions simultaneously into the spray-tank, and the mixture will

be ready for use. The best results are obtained when the application is made as soon as possible after blending the two solutions. If allowed to stand over eight hours the fungicidal properties largely depreciate. Stock solutions of the ingredients may be kept satisfactorily, but, as just stated, they should not be mixed until required. Bordeaux should be neutral or slightly alkaline ; .it should never contain an excess of copper sulphate. It should give no reaction to litmus paper. A bright steel knife-blade dipped in the acid mixture is quickly covered with a deposit of metallic copper. Again, free copper is quickly detected if a little of ■ the mixture is placed in a saucer and a drop of solution of ferro-cyanide of potassium is poured on it, when it will immediately assume a muddy brown appearance. This precaution is important when spraying during the growing-period. . (2.) Lime-sulphur. This is , sulphur made into a liquid form by boiling it in lime-water. Large users generally make their, own. It may be made as follows: 'Sulphur, 100 lb. ; rock lime (95 per cent, pure), 50 lb. ; water, 50 gallons. Slake the lime carefully and strain it into an iron boiler. Mix the sulphur to a paste and add it’ to the lime-water, also sufficient water to make it up to 50 gallons. Boil the mixture until all the sulphur is dissolved (about, an hour), taking care to replace the water evaporated. Solutions made in this way usually register 20° to 25 0 Beaume. To make -correct dilutions the specific gravity of the concentrate should be ascertained by means of the Beaume hydrometer, and reference made to the dilution table on page 48. (3.) Finely Precipitated- Sulphur (In Paste Form). — The commercial proprietary preparations of this material are generally used. CONTROL TREATMENTS. Apple, for Black-spot and Powdery Mildew. — In spring, as the buds are breaking (green-tip), apply lime-sulphur (33 0 Beaume test), 1-10. As the flower-buds break (pink), make another application, 1-35 or 1-50. When the petals fall give the calyx spray, 1-80 or 1-100. Follow at intervals thereafter, as required, at 1-125. In some localities it has been found necessary to use the stronger fungicide bordeaux, 6-4-50, at the green-tip, and 3-4-50 at the pink stage, subsequent sprays being limesulphur, 1-100 or 1-125. On some varieties the use of bordeaux has a tendency to cause russeting of the skin of the fruit. Some varieties that are specially tender, and trees in weak condition, are sometimes sprayed at the’ calyx stage and after with finely precipitated sulphur, 1 lb. to 8 or 10 gallons of water. (See illustration of various stages of blossom-development.) Pear, for Black-spot. Apply bordeaux, 6-4-50, at green-tip, 4-4-50 at the pink, and 3-4-50 at the calyx stage ; and at intervals thereafter as required. . . • • ■ Stone - fruits, for . Leaf-curl, Shot-hole, Bladder-plum, and Brownrot. — Apply bordeaux, 8-6-50, as the buds commence to move, and 6-4-50 at the pink stage. Where brown-rot is prevalent trees should •be sprayed with lime-sulphur, 1-125, when the fruit has set, and at intervals of about twenty-one days thereafter till within a week or so of picking. It is also necessary to go over , the trees carefully every week during the fruiting season and gather and destroy affected fruit.

of is when using first specific of (To a prepare standard find of a figures of of in line figures top of and specific make of apply lime-sulphur.)

Bluestone solution — lb. bluestone to 15 or 20 gallons water —■ may be applied when the trees are dormant, in place of the first abovementioned bordeaux spray. ■ , Citrus-fruits, for Verrucosis, Grey-scab, &c. Apply bordeaux, 4-4-40, or lime-sulphur, 1-50, in spring, when the main crop has set, and again in the autumn. ' . COMBINED SPRAYS. Some sprays may be combined with others without detriment, and labour thus saved. Bordeaux and arsenate of lead may be applied together ; also lime-sulphur and arsenate of lead ; and lime-sulphur, arsenate of lead, and Black Leaf 40. It is advisable to make a heavy dilution of these ingredients before mixing them. In combining limesulphur with arsenate of lead, , when the trees are tender it is advisable when diluting the arsenate of lead to include thejmilk of an equal weight of lime. SPREADERS. . The use of spreaders in conjunction with the different sprays is a practice that is growing in popularity. It is claimed that this practice ensures instant and prolonged adhesion, an even distribution, and a better suspension of the ingredients, and that sprays which lack these qualities are greatly benefited by the inclusion of such a substance. There are several proprietary spreaders on the market, but powdered casein is claimed to serve the purpose quite satisfactorily. It may be prepared as follows: Place 5 oz. casein in a vessel and slowly add | gallon water, stirring well. Slowly slake 5 oz. lime and make up to | gallon. Pour the lime-water slowly into the casein, stirring well. Put the requisite quantity of water into the spray-tank, add the casein mixture, agitate thoroughly, then add the other ingredients. This is sufficient for 100 gallons of spray mixture. GENERAL. ' It should be recognized that owing to differences in climatic conditions and other varying factors only generalities can be dealt with in an article such as this. . For this reason orchardists desirous of obtaining the best results by the most economical methods should consult the Orchard Instructor in their respective districts, the Instructor being in a position to give more specialized advice. . Note. The foregoing matter has been issued as Bulletin No. 117, superseding Bulletin No. 82, Orchard'Pests and Diseases : Directions for Control.” Editor. Honey-export Control — The poll of honey-producers taken in December resulted in the proposal that the Act be brought into operation being carried by 253 votes to 9. New Rabbit Districts. — The constituting of the Hunterville and Oroua Rabbit Districts (Wellington) and the Waipipi Rabbit District (Auckland), for the purposes of Part III of the Rabbit Nuisance Act, was gazetted last month. Quarantine on Dogs.— The period of quarantine on dogs imported into New Zealand from Britain has been reduced from six months to sixty days. The amending regulation came into force on nth December, 1924.

Beaume. I-IO. 1-15. 1-20. 1-25. 1-30. 1-40. 1-50-1-60. I ■ ■ 1-70. j 1-80. 1-90. i-ioo. I-IIO. 1-120. 1-125. 1-70. 1-80. 1-90. I-IOO. I-IIO. 1-120. 1-125. i5° 4-6 6-8 9-i II-4 13’6 18-2 22-8 27’3 31’8 36’4 40’9 45’5 50-0 54’5 56-8 i6° 4-8 77 97 I2-I i4’5 19-4 24’3 29-1 33’9 38’8 43’6 48’5 53’3 58-2 6o-6 0 17 5-2 77 10-3 12’9 i5’5 20-6 25’8 30-9 36-1 41-2 46-4 5i’5 567 6i-8 64-4 i8° - 5’5 8-2 . 10-9 13-6 16-4-21-8 27’3 327 38-2 43’6 49-i 54’5 6o-o 65’5 68-2 0 19 5'8 8-6 u-5 14-4 17’3 23-0 28-8 34’5 40’3 46-1 ■51’8 57’6 63’3 69-1 72-0 20° 6-i 9-i 12’1 15-2 18-2 24-2 30’3 36’4 42'4 487 54’6 6o-6 66-7 727 75’8 21° 6-4 97 12’7 i5’9 19-1 25’5 31-8 38-2 44’5 50’9 57’3 63-6 70-0 76-4 79’5 22° . -67. io-o 13’3 167 20-0 267 33’3 40-0 467 53’3 6o-o 667 73’3 8o-o 83’3 23° 7-o 107 13-9 17-4 20-9 27-9 34’8 41-8 48-8 55’8 627 697 767 83’6 87-1 24° 7’3 10-9 147 18-2 21-8 29-1 36’4 43’6 .50’9 58’2 65’5 727 8o-o 87’3 90-9 25° 7-6 n-4 15-2 19-0 227 30’3 37’9 45’5 53’0 6o-6 68-2 75’8 83’3 90-9 947 26° . 7-9 n-8 15-8 197 23-6 3i’5 39’4 47’3 55’2 63-0 70’9 78-8 86-7 94’5 8 9 27° 8-2 12-3 16-4 20-5 24’5 327 40’9 49-1 57’3 65’5 73’6 8i-8 90-0 98-2 102-3 28° 8’5 127 17-0 21-2 25’5 33’9' 42’4 50-9 59’4 67-9 76-4 84-8 93’3 ioi-8 106-1 0 29 8-8 13-2 17-6 22-0 26-4 35’2 43’9 527 617 70’3 79-1 877 967 105-5 109-8 30° 9-1 13-6 18’2 227 27-3 36-4 45’5 54’5 63-6 72’7 8i-8 90-9 100-0 109-1 113-6 3i° 9-4 ■I4-I 18’8 23’5 28-2 37’6 47’0 56-4 65’8 75’2 84’5 93’9 103-3 112-7 117-4 32° 97 147 19-4 24-2 29-1 38-8 48’5 58*2 67-9 77’6 87’3 97’0 106-7 116-4 121’2 33° io-o i5’0 20-0 25-0 30-0 40-0 50-0 6o-o 70-0 8o-o 90-0 100-0 IIO-O 120-0 I25-O 34° 10-3 i5’4 20-6 25’8 30-9 41-2 5i’5 6i-8 72-1 82-4 92’7 103-0 ii3’3 123-6 128-8 35° io-6 15-9 21’2 267 31-8 42’4 53’0 63-6 74’2 84-8 95’5 106-1 116-7 127-3 132-6

REFERENCE TABLE FOR STANDARDIZING HOME-MADE LIME-SULPHUR SOLUTION BASED ON A 33° BEAUME STANDARD.