Issue link: http://read.dmtmag.com/i/89919
AUSTRIAN RESEARCHER tests seaweed claims M anufacturers of biostimulants derived from seaweed, or algae, say the products can provide multiple benefits when applied to crops. Purported benefits include better root growth, resist- ance to weather-related stress, increased plant vigor, and better uptake of micronutrients. Some products are said to improve flower bud formation or fruit set, leading to better quality fruit and higher yields, while others are said to stimulate cell division, thus improving fruit size. However, Austrian researcher Dr. Thomas Rühmer, who began a multiyear trial with Golden Delicious apples in 2010 to investigate the effects of algae-based products on production levels, fruit size, and russeting, has found inconsistent results so far. The products he is testing are: Figure 1 Effect of extracts on yield 25 20 15 10 5 0 • Wuxul Ascofol (Aschophyllum nodosum seaweed extracts with boron, manganese, and zinc) from Aglukon • Goëmar Florea (containing A. nodosum) from Belchim Crop Protection • Alga Mix B Mg (containing an algae mixture with mag- nesium and boron) from L. Gobbi • PhytoAS (containing pure seaweed sap) from ERB- agrar • Phytoamin (containing marine algae liquid) from Lebosol-Dünger GmBH. All products were applied in 2010 and 2011 according to the manufacturer's recommendations: four times at 10-to-14-day intervals starting at bloom. Some of the products had a positive influence on pro- duction levels, resulting in larger apples or a smoother skin. However, the effects differed strongly in 2010 and Figure 2 Effect of extracts on size 100 2010 2011 10 20 30 40 50 60 70 80 90 0 2010 2011 Figure 3 Effect of extracts on russet 2011, reported Rühmer, who is based at the Haidegg Agriculture Research Center in Graz. In 2010, Phytoamin and Wuxal Ascofol had a small, but not statistically significant, influence on the production level but not in 2011 (see Figure 1). In both 2010 and 2011, use of all the products resulted in more apples in the 80 mm ((3-1/8 inch) and larger size range than the control (see Figure 2). In 2010, Wuxal Asco- fol had the greatest effect, but in 2011, Alga Mix had the greatest effect. In 2010, applications of Wuxal Ascofol and Phytoamin resulted in fewer russeted apples, and the other products had no influence on russeting. In 2011, none of the prod- ucts reduced russeting (see Figure 3). The research is being continued in 2012. —G. Warner Source: Dr. Thomas rühmer, Haidegg Agricultural research center, Austria. Source: Dr. Thomas rühmer, Haidegg Agricultural research center, Austria. diseases and insects on crops, including apples, in their promotional materials. The trial had five differ- ent cultivars: Ginger Gold, Honeycrisp, Liberty, Macoun, and Zestar. The treatments were applied according to the Edwards Equipment Company offers forklifts to fit your tractor, skid steer, or wheel signed Dyna-Cutter for narrow rows is a rotary mower that is short coupled, low profile, dual spindle with coun- ter rotating blades for side or rear discharge. Manufacturing Excellence for over 60 years. loaders. The newly de- manufacturers' guidelines. Seven applications were made each season. The foliage was assessed in late July and early August for incidence of European red mite, two- spotted spider mite, predacious mites, leafhoppers, lady beetle larvae, black hunter thrips, and cecidomyid fly larvae. Leaves were also evaluated for damage by Japanese beetle, leafhoppers, and leafminers. Fruit was assessed for injury by plum curculio, tarnished plant bug, apple maggot, European apple sawfly, codling moth, ori- ental fruit moth, lesser apple worm, and leafrollers. There were no differences in the populations of preda- Forklifts Dyna-Cutter Our Front 3-Point hitch enables implements to be added to the front of your tractor, while our Brush Spider will sweep the tree rows clean of debris and prunnings. For more information view our web site, call us, or meet us at one of the upcoming shows. cious mites, cecidomyid fly larvae, or lady beetle larvae. In 2009, black hunter thrips, a predator of phytophagous mites, were found on fewer leaves on the Stimplex-treated trees than on the untreated trees. However, there was no effect on pest mite populations. "Therefore, the A. nodosum extract materials studied in this experiment do not appear to provide any benefit in phytophagous mite management compared to the non- treated control," Bradshaw reported. Mite populations were high throughout the orchard, Front 3-Point Hitch Double Brush Spider Equipment will be on display at the following shows. Northwest Hort Show Yakima December 4-5, 2012 424 Northwest Ag Show Portland January 29-31, 2013 E-189 World Ag Expo Tulare February 11-14, 2013 I-3 4312 Main Street Union Gap WA 98903 800-452-5151 509-248-1770 Web Site: www.Edwards-Equip.com E-mail: sales@Edwards-equip.com 42 NOVEMBER 2012 GOOD FRUIT GROWER Bradshaw said. The orchard was managed with an inten- sive, organically acceptable spray program for scab and insects that is typical for a Northeast orchard and included applications of sulfur or lime sulfur as well as kaolin clay. Those materials are known to negatively impact predatory mites and have been shown to lead to flare-ups of phytophagous mites. The seaweed extracts did not affect the amount of fruit Fruit damage damage from European apple sawfly, plum curculio, codling moth, oriental fruit moth, lesser appleworm, or leafrollers, or the incidence of those pests in either year. In 2009, Stimplex-treated trees had a greater incidence of leaves with lyonetia (apple leafminer) mines than the untreated trees. Source: Dr. Thomas rühmer, Haidegg Agricultural research center, Austria. In 2009, some varieties in the control plot had fruit damaged by apple maggot, whereas the seaweed treat- ments had none. In the control plot, Honeycrisp and Macoun also had no damage, but Ginger Gold had 0.7 per- cent fruit damage, Liberty 1.3 percent, and Zestar 0.7 percent, for an average of 0.5 percent across cultivars. In 2010, Honeycrisp in the control plot had 4.8 percent apple maggot damage, but the rest of the control varieties had none. Trees treated with the seaweed products had no damage. Although reductions in apple maggot incidence result- ing from the treatments were noticeable, the pest pressure was sufficiently low, even in the untreated control, that reductions in damage would not be economically impor- tant, Bradshaw said. He believes the seaweed extracts might be altering or masking the scent of ripening fruit, which the apple maggot flies use to locate fruit to infest. Bradshaw concluded that use of seaweed extracts could not be recommended as a way to improve pest management in an organic apple orchard. However, fur- ther research on the effects of the materials on apple mag- got in an orchard where there is higher pest pressure could be warranted. —G. Warner www.goodfruit.com KILOGRAMS PER TREE Control Wuxal Ascofol Phytoamin PhytoAS Alga mix B Florea PERCENT OF FRUIT MORE THAN 80 MM Control Wuxal Ascofol Phytoamin PhytoAS Alga mix B Florea