THE CONTROL OF RASPBERRY BEETLE.

Auckland Star, Volume LXV, Issue 285, 1 December 1934, Page 6 (Supplement)

THE CONTROL OF RASPBERRY BEETLE.

The following article appears in the "Annual Report of the Horticultural Superintendent for Norfolk County Council," and will be of interest to raspberry growers:— Very satisfactory results have been obtained by using Derris Root powder. The weight of crop increased by one ton of fruit on these plots, which is due partly to potash dressing but mainly to absolute control of beetle. The dust was applied at each application to both sides of the rows. The powder enveloped each part of the row in a cloud of dust, and thoroughly covered each part of the canes. A geared hand blower was used for this purpose, and the deposit of the dust was found on every leaf inspected and in all parts of the canes. The dustings were carried out as follows: — First Dusting. —May 25, 1933 (November, New Zealand), green bud stage. Second Dusting.—June C, 1033 (December, New Zealand), just as flowers were opening. Third Dusting.—June 15, 1933 (December, New Zealand), advanced petal fall stage. The first dusting has a pronounced toxic effect, while the second and third dustings caught beetles that had emerged from the soil after the first dusting, and also destroyed any larvae which had come from the beetles that has been missed in the operations. A careful search among the plots revealed a few beetles that had either been missed or were late in emerging, but it was very difficult to find either beetles or larvae after the dusts had been applied. One row of raspberries was left untreated as a control. This row showed an average of 31 per cent clean fruits. On the dusted rows the fruit was 97 per cent clean. All the early pickings on the treated rows were absolutely clean, but towards the end of the season a few larvae appeared in some of the berries. This infestation probably resulted from a few beetles that were found, but this late infestation is quite contrary to our experience in previous years, as we found on untreated plantations a great reduction in the infested berries at the end of the season, and this actually happened on the control row this year at Burlingham. One cwt of dust per acre was used for each of the three dustings. The cost of the material for the three dustings was £5 14/. The actual increase in the crop weights on the trial plots was 13J cwt, and selling these at £2 per cwt, the extra receipts came to £27 10/.