If salt is used, it should be scattered freely in the dry form. Caution is necessary where it is liable to be washed on to lawns, lest it damage the grass borders. Carbolic acid or arsenical poisons are preferable, being both less liable to wash and more enduring in their action. One quart of crude carbolic acid in eight gallons of water, or one pound of either arsenical compound mentioned above in a like amount of water, will suffice to cover a square rod or more of surface; and one or at most two applications per year will be sufficient.

Walks should be so made that weeds cannot grow in them. This can be done by making a deep stone foundation and filling between the stones with cinders, coal ashes, or other similar material.

List of weeds that may be controlled by means of chemical sprays.

The following named weeds may be eradicated or largely subdued in cereal grain fields through the use of chemical sprays: False-flax, worm-seed mustard, tumbling mustard, common wild mustard, Shepherd's purse, pepper-grass, ball-mustard, corn cockle, chickweed, dandelion, Canada thistle, bindweed, plantain, rough pigweed, king-head, Red River weed, ragweed, cocklebur.

Weeds on which field spraying methods as- now in use are not effective.

The following weeds are not effectively controlled by chemical sprays as now used : Hare's ear mustard, French weed, pink cockle, perennial sow-thistle, lamb's-quarters, pigeon-grass, wild oats, chess, quack-grass, sweet-grass, or holy-grass, and wild barley.

Results of spraying with iron sulfate for the control of weeds (Rhode Island Sta.)



Common Name

Botanical Name

Yellow dock ....

Rumex crispus

Plants checked for about three weeks.

Sheep sorrel ....

Rumex Acetosella

All blossoms killed and 90 per cent of all leaf growth.

Common chickweed

Stellaria media

Killed. Can be controlled.

Mouse-ear chickweed .

Cerastium vulgatum

Practically killed, but not so easily as the common chickweed.


Portulaca oleracea

Young leaves and tips of stems killed. Old growth not injured.

Results of spraying with iron sulfate — Continued



Common Name

Botanical Name


Ranunculus bulbosus


Shepherd's purse

Capsella Bursa-pastoris

Completely controlled.

Five-finger ....

Potentilla Canadensis

Young plants killed, old plants seriously injured.

Poison ivy ....

Rhus Toxicodendron

Not injured when sprayed with concentrated solution.

Wild carrot ....

Daucus Carota

Only slightly injured.

Common plantain .

Plantago major

Leaves badly spotted, plant not killed.

Rib grass, narrow-leaved plantain .

Plantago lanceolata

Young plants killed, old ones prevented from maturing seeds.

Robins plantain .

Erigeron pulchellus

Blossom buds killed, no seed formed.


Achillea Millefolium

Practically no injury.

With the exception of the application to the poison ivy, the iron sulfate was applied as a 20 per cent solution, using it at the rate of 100 to 150 pounds per acre.

At the South Dakota Station the following weeds were entirely killed by the use of iron sulfate: —

Wild mustard (Brassica arvensis); ragweed (Ambrosia artemisaefolia); king-head or greater ragweed (Ambrosia trifida); bindweed (Convolvulus Sepium); marsh elder (Iva xanthifolia); milkweed (Asclepias sp.); pepper-grass (Lepidium Virginicum); pigweed (Amarantus sp.); sweet clover (Melilotus alba and M. officinalis). Those that were more or less badly injured: Russian thistle (Salsola Kali); sunflower (Helianthus sp.); dandelion; dock (Rumex crispus); thistle (Carduus) sp.); white clover (Trifolium repens); red clover (Trifolium pratense); alfalfa (Medicago sativa). The following were but slightly injured: plantain (Plantago major); sheep sorrel (Oxalis violacea); prairie rose; lamb's quarters (Chenopodium album). Grasses in general, including the grains (wheat, oats, corn, barley, and speltz were sprayed in our experiments) were none of them seriously injured.

According to the Ohio Station, salt has thus far proved the best spray tested for Canada thistle, poison ivy, yarrow, and horse-nettle. In the Northwest, sodium arsenite (11 pounds sodium arsenite in 50 gallons water) is given first rank. Salt is probably the most effective to destroy dandelion and some other weeds. Iron sulfate is very satisfactory to kill mustard weeds, ragweed, white-top, yarrow, and we believe a great many other broad-leaved weeds. Neither the salt nor the iron sulfate is regarded as offering any risk of application to pastures in which stock is running. Sodium arsenite is a very active poison, and rather dangerous for that reason. Calcium chlorid (of same strength as common salt solution) has done very well where tested, but appears to be slightly inferior to salt. Copper sulfate solutions may be used in grain fields for mustards, especially, but owing to the poisonous nature of the copper sulfate, it has a very narrow range of application.

Experiments by the Cornell Station gave the following general conclusions : Wild mustard growing with cereals or peas can be destroyed with a solution of copper sulfate, without injury to the crop. A 3 per cent solution (about 10 pounds to the barrel, or 40 gallons of water), at the rate of 40 to 50 gallons per acre, gives very satisfactory results.