In the United States and Canada field-mice are found in all parts that are liable to girdle the stems of young orchard trees. A certain preventive is to throw a small mound of earth around the lower part of the stem late in autumn. For some reason not known to the writer the mice never ascend the mound, but run their trails under the snow around it. If the mounding has been neglected damage may later be largely prevented by tramping the snow firmly around the lower part of the stem. If there is no snow, and mice are numerous, binding the stems with woven mosquito-bar wire will prevent damage. The wire will also protect from rabbits. But washing the stems with unpalatable solutions is the usual method of protecting trees from rabbits. The best wash yet tested is made by adding to one gallon of stale urine one quart of fresh lime, and one pint of pine tar stirred in when hot. Then stir in flowers of sulphur until it makes a wash that can be applied with a stiff brush or old broom. The writer has not known even the Jack-rabbit, or the European rabbits, to touch a stem covered with this wash, that sticks well to the stem over winter usually. But during rainy winters it sometimes happens that a second wash is necessary where rabbits are numerous.
The crown borer often fatally injures young apple- and quince-trees. But it is easily managed by washing the stems about the first, middle, and last of June with a strong solution of soap and water. Before applying the wash search for the castings of the borers around the lower part of the stem. If any are found they can be crushed in their burrows without cutting the bark with a flexible wire that will follow the burrow. If the larva is reached the evidence will be given on the point of the wire. With this treatment the writer with forty years' experience has never sustained much injury by borers, while neighbors who trusted to cutting out the larva have lost hundreds of trees.
On young apple-trees the ring or cylinder of eggs covered with waterproof varnish can easily be detected, detached, and burned during the leafless period of winter. If any escape it is far better to twist out the nests with a forked stick than to burn them out, as often practised with kerosene, which always injures the bark and leaves.
The rodents and insects noticed at this time the orchard ist comes first in contact with in orchard management. A few of the leading insects encountered later will be discussed in the chapter on spraying. But we now have special books on spraying copiously indexed that can be used at the nick of time when exact information is needed to guide the work of insect extermination or control.