Orchard Conditions Research Articles

Changes in the nitrate and sulfate content of the soil solution under orchard conditions

Abstract does not appear. First page follows. In 1922, the Division of Pomology of the California Agricultural Experiment Station began an investigation on the maintenance of soil fertility in deciduous orchards. For this purpose a field of approximately twelve acres was selected and half of it planted to deciduous fruit trees. This will hereafter be referred to as block A. The following year, 1923, the other half was set out. It will be designated block B. The soil in the field selected varied from a fine sandy loam to a loam of the Yolo series. The water table stood at approximately sixteen feet. The entire volume of soil above the water table was in horizon A. There were some slight modifications in texture before that depth was reached, but neither gravel nor clay was found. Crop History of the Field Used The crop history of this field before the planting of the orchard is of interest.† In the summer of 1908, this area was levelled for alfalfa irrigation. Previous to this time it had been in grain for an indefinite period, probably about fifty years. In the spring of 1909, it was planted to alfalfa. From 1909 to 1913, there is no available record as to yields or irrigation frequency, but it is supposed that the entire area had essentially the same treatment.

Preliminary Report on Attrahents for Peach Insects

A number of chemicals are reported which were slightly attractive to various peach insects under orchard conditions. No attrahents were found for injurious peach insects which showed much promise of being of value from the standpoint of control.

Are Codling Moths Attracted To Lights?

For many years entomologists have agreed that the codling moth, Carpocapsa Pomonella L., is not attracted to lights. A test, in 1926, with light in a closed storage room, in which codling moths were emerging, however, showed that they were readily attracted to a small light. A test in an orchard subsequently showed them only slightly attracted to a light trap in a tree top. Another test, in 1927, which was much more comprehensive. showed them readily attracted in large numbers to varying intensities of light in light traps operated under normal orchard conditions.

Bait-Pails as a Possible Control for the Oriental Fruit Moth1

This paper contains: (1) a report of a preliminary trial of the bait-pail method of control under orchard conditions; (2) the answers to certain questions concerning the feeding of females which are of importance to the problem; (3) a consideration of the best type of pail to maintain maximum catch and minimum evaporation; (4) a summary of numerous baits of the fermenting and non-fermenting types; and (5) a detailed study of the fermenting process in baits with special reference to their attractiveness to the oriental fruit moth, Laspeyresia molesta Busck.

The efficacy of lead arsenate in controlling the codling moth

does not appear. First page follows. The investigator who undertakes an orchard spraying experiment for the purpose of determining the value of one or more elements in the spraying method of controlling the codling moth, Carpocapsa pomonella (Linn.), is confronted by a large number of unknown and uncontrollable factors which influence in various ways and degrees the results of his experiment. Conclusions arrived at under such conditions of experimentation are likely to be lacking in explicitness and accuracy, and they may sometimes be wholly erroneous. It is a well known fact that the vast literature on codling moth spraying is replete with contradictory experimental data, and discordant opinions and beliefs. A number of points of primary importance regarding this method of control have continued to remain largely in the realm of assumption and theory every since spraying was first employed in codling moth control nearly fifty years ago. Spraying tests have been confined almost without exception to orchard conditions. While assisting in some orchard experiments during the summer of 1917 to determine the relative merits of spraying and dusting with lead arsenate as a means of controlling this pest, I was impressed by the fact that so many variable factors were encountered as to render the resultant data of very doubtful value. Similar experiences met with in subsequent investigations and a study of the investigations of other entomologists emphasized the desirability of more accurate experimentation than could be accomplished under orchard conditions. It was during the late summer of 1920 that the idea was conceived of performing experiments with freshly hatched codling moth larvae in the laboratory. The work started that year was continued in a limited way in 1921, while fairly extensive studies were made in 1923 and 1924.

Spreader Tests on Apples and Peaches: A Second Report

The efficacy of a casein spreader (Kayso) in the commonly recommended sprays for apple and peach has been studied for the second season. These sprays, with and without the spreader, were mixed by the writers and applied by the regular orchard force. The second season's results parallel those of the first year's work. There is no indication that the incorporation of the spreader with the usual sprays influenced the protection of the fruit from insects and diseases. The conclusion is that the use of a casein spreader (Kayso) in the apple and peach sprays under orchard conditions in Virginia is not justified from the standpoints of effectiveness and economy.

Dormancy and Hardiness in the Plum

1. In the plum there are widely differing degrees of dormancy among the different species and varieties. There appears to be a definite relation between dormancy and hardiness. Assiniboine is extremely hardy and its dormancy is very profound, in contrast with Tonka and Stella, two semihardy varieties in Minnesota, which appear to enter real dormancy for only a very short period in early winter, if they do so at all. 2. During the period of dormancy the moisture content of the semihardy varieties fluctuates with the temperature. Periods of low temperatures are accompanied by a loss of moisture from the leaf and fruit buds, and higher winter temperatures, which are seldom above freezing in Minnesota, by an increase in moisture content. In comparison with the semihardy varieties the moisture content of Assiniboine remains at a definite and fairly constant minimum throughout dormancy. 3. When the fluctuations in the moisture content of buds were found to occur under orchard conditions, this phase of the probl...

The Susceptibility of Adults and Eggs of Pear Psylla to Spraying Mixtures

In summarizing briefly this paper the chief points presented are,- (1), that the emergence of adults from winter quarters, deposition of eggs and migration of larvae occur with very little intermingling at di8tinct time prriod8 and arc, to a large degree, coincident respectively with certain life events of the pear tree, as the swelling of the buds, development of the blossom clusters, and opening of blossoms; (2), that the psylla in each of its life stages is sensitive to certain spraying mixtures. Experiment in 1910 indicated the possiblitity of protecting pear orchards by a single treatment to kill either the adults, or eggs, or nymphs. The presence of the psylla in destructive numbers in 1911 in the leading pear growing sections of western New York afforded exceptional opportunities for a large series of tests to demonstrate, under ordinary orchard conditions, the susceptibility of hibernating “flies,” eggs and nymphs to various mixtures. Quite a number of growers freed their orchards of the pest by spraying for the “flies” with miscible oils, home-made emulsions or commercial nicotine preparations. The majority of orchardists, after spraying for the “flies,” applied limesulphur solution at winter strength to destroy the eggs. In only a few plantings was it necessary to make a third treatment with a nicotine spray to kill the young nymphs. In summing up the results of the spraying operations it was concluded that the chief factors which make for the successful control of the psylla are (1) a knowledge on the part of the grower of the different stages of the insect; viz., hibernating “flies,” eggs and nymphs; (2), an understanding of the activities of the psylla during the dormant season until trees blossom; and (3), thorough work in spraying.