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SPOREKILL® GIVES POTATO SPRAY PROGRAM EXTRA GO! Johann van der Vyver | Product Specialist | ICA International Chemicals

Many potato growers have benefited in the past and still benefit from Sporekill®’s foliage sanitising capabilities when included in their standard pest control spray program. Frequent positive comments by South African potato producers and documented successes by Brazilian growers were recently confirmed by two comprehensive demonstration trials in the Western Cape Province of South Africa. FOLIAR DISINFECTION - One of the most successful and popular applications of the agricultural sanitiser Sporekill® (Reg. no. ACT29GNR529/27555/070/210) is foliar sprays on crops either on its own or (especially) within a spray program. The success can be attributed to Sporekill®’s ability as plant sanitiser to: • reduce plant disease pressure by drastically reducing fungal and bacterial pathogen inoculum on foliage upon contact; • destroy various stages of fungal development on contact; and • kill resistant populations. BRAZIL FEEDBACK - During 2006 and 2007 commercial demonstration trials on potatoes were conducted in Brazil. Sporekill® was included within standard spray programs and compared with the standard spray programs. The results were a huge success. Where Sporekill® was included, the plants appeared more healthy and superior (Figures 1 and 2).

Figure 1: Foliage of potato plants (Vivaldi variety) in Brazil where Sporekill® was included in the spray program (right) appeared healthier than plants sprayed with the spray program (left). Main disease presence: Erwinia sp.

Figure 2: Foliage of potato plants (Cupido variety) in Brazil where Sporekill® was included in the spray program (right) appeared healthier than plants sprayed with the spray program (left).

SOUTH AFRICAN DEMONSTRATION TRIALS - Many comments, similar to the Brazil feedback, were received from South African potato growers over the years. In addition, commercial demonstration trials were conducted during the South African 2011/ 2012 season. The trials were conducted at two different commercial farmers, one near Reedlinghuys (BP1 variety) and the other near Clanwilliam (Lady Rosetta variety) in the Western Cape Province of South Africa. At both locations Sporekill® was included with each application of the spray program and compared with the standard program. Evaluations included frequent assessments of general foliar disease incidence, as well as frequent assessments of specific disease incidence on foliage (Botrytis at both locations). At the Reedlinghuys location potatoes were harvested according to commercial practice, where after the yield and remuneration were determined. RESULTS - The results attained confirmed Brazilian feedback and South African comments. At the Reedlinghuys location plants sprayed the standard program had a lot more general foliar disease incidence compared to where Sporekill® was included (Figures 3 to 5). The difference became significant from week 8 after emergence (Figure 5). Not only was the general disease incidence lower where Sporekill® was included, but the intensity of disease increase (gradient) was also a lot less. The latter and the huge difference at week 14 (Figure 5) can largely be attributed to Sporekill®’s broad spectrum foliar sanitation ability in addition to the standard program. SPRING 2012

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Figure 3: Foliage from potato plants (BP1 variety) in South Africa where Sporekill® (right) was included in the spray program appeared healthier than plants sprayed with the spray program (left).

At both locations the Botrytis incidence on the foliage was lower where Sporekill® was included (Figures 6 and 7). The differences were significant from week 8 onward, with huge differences at week 14 (Figures 6 and 7).

Figure 4: Illustration of general superior appearance of plants (BP1) where Sporekill® (left) was included.

Figure 6: Botrytis incidence on foliage over time of potato (BP1 variety) plants sprayed with a standard program, as well as standard program plus Sporekill®. [Disease rating based on the following percentage foliar Botrytis symptoms: 0 = no visible disease symptoms; 1 = 1 – 20%; 2 = 21 – 40%; 3 = 41 – 60%; 4 = 61 – 80% and 5 = 81 – 100%]

Figure 5: General foliar disease incidence over time of potato (BP1 variety) plants sprayed with a standard program, as well as standard program plus Sporekill®. [Disease rating based on the following percentage foliar disease symptoms: 0 = no visible disease symptoms; 1 = 1 – 20%; 2 = 21 – 40%; 3 = 41 – 60%; 4 = 61 – 80% and 5 = 81 – 100%]

Figure 7: Botrytis incidence on foliage over time of potato (Lady Rosetta variety) plants sprayed with a standard program, as well as standard program plus Sporekill®. [Disease rating based on the following percentage foliar Botrytis symptoms: 0 = no visible disease symptoms; 1 = 1 – 20%; 2 = 21 – 40%; 3 = 41 – 60%; 4 = 61 – 80% and 5 = 81 – 100%]

The healthier potato plants (sprayed with standard program plus Sporekill®) at the Reedlinghuys location resulted in a significant higher yield and remuneration (Table 1).

Table 1: Yield and remuneration values for potato plants sprayed with a standard program, as well for potato plants sprayed with standard program plus Sporekill® (variety BP1).

TREATMENT

Mass/ ha (10 kg bags)

Mass/ ha (7 kg bags)

Remuneration (10 kgbags*)/ ha

Remuneration (7 bags*)/ ha

Total yield /ha

Total remuneration/ ha

Standard program

24 368 kg

15 473 kg

R54 828

R36 671

39.84 T

R91 499

Standard program plus Sporekill®

30 635 kg

21 687 kg

R68 928

R51 398

52.32 T

R120 326

*Remuneration calculated according to market price at the time of R2.25/ kg for 10 kg bags and R2.37/ kg for 7 kg bags.

Should you require any more information on the information presented or on how to benefit similarly, please contact you nearest Hygrotech Office or johann@icaonline.co.za SPRING 2012

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