Serenade Prime contains viable spores of the highly active QST 713 strain of Bacillus subtilis. These beneficial bacteria live on the plant root surfaces and in the soil around the plant roots.
Beneficial Bacteria (cont from last issue)
Serenade® Prime was applied via a soil drench to each tree at a rate of 35 mL per tree at the time of planting. The beneficial relationship between the plant roots and the bacteria can enhance plant growth and productivity.
If applied at planting and during root flushes it is reported to play a role in improved nutrient exchange, crop vigour and uniformity.
Chloropicrin
Rural Telone C-60 has a high chloropicrin content and is better for use in heavier, wetter, colder soils where rapid volatilisation will allow quicker release of the product from the soil to prevent the need for extended plant-back periods.
It targets soil-borne diseases including those caused by Fusarium, Verticillium, Rhizoctonia and Pythium, as well as helping to control parasitic nematodes, garden centipedes and wireworms, and suppress weeds.
An accredited contractor applied the Rural Telone C-60 at a rate of 300L/ha. This needed to be applied at least three weeks prior to planting to avoid any phytotoxic effects. The trees were planted six weeks after treatment.
Latest results
Trunk diameter, stem elongation and fruit counts were measured each autumn for three years after planting.
The results after the third growing season clearly show which treatments have given the trees the best start and enabled good growth into the third leaf stage.
May 2020 (3rd leaf) measurements show the trees on the chloropicrin-treated ground had a trunk diameter 8mm larger than the closest-performing treatment, the beneficial bacteria (Figure 1).
Stem elongation at 3rd leaf shows that the trees planted into soil treated with chloropicrin have produced longer leaders, followed by the trees planted into soil with the beneficial bacteria treatment and then those that underwent the standard practice treatment of Metham Sodium.
The trees to which beneficial bacteria were applied at planting had more leaders than trees in the other treatments.
The shoot mass was calculated for each treatment by multiplying the average number of shoots and average shoot length for the monitored trees.
For the 3rd leaf results the trees treated with beneficial bacteria had the largest mass closely followed by the trees in the chloropicrin-treated soil (Figure 2).
This year was the first in which apples were harvested from the block. Fruit counts were undertaken on the five monitoring trees in each treatment. The chloropicrin and beneficial bacteria treatments had the equal highest number of apples at 24 apples per tree, followed by the biofumigation treatment of mustard and rocket (Figure 3), which yielded an average 20 apples.
Biological treatments vs chemical treatments (cont next month)
See this article and Figures in Tree Fruit Dec 2020
