Articles
ALTERNATIVES TO PCNB FOR CONTROLLING GRAY BULB ROT ON TULIPS
Article number
886_44
Pages
311 – 317
Language
English
Abstract
Gray bulb rot, caused by Rhizoctonia tuliparum, has the potential to cause significant losses on tulips and bulbous iris.
When bulbs are planted in infested soil, infected plants often fail to emerge or die shortly after emergence, resulting in the formation of missing or dead patches of plants in the field.
In-furrow applications of Terraclor (PCNB) are applied to most tulips at the time of planting in the Pacific Northwest to control this disease.
During the past several years, a series of replicated field trials have been conducted to compare the efficacy of in-furrow applications of Heritage 50WG (azoxystrobin), Medallion 50WP (fludioxonil), and Moncut 70DF (flutolonil) to Terraclor 75WP in controlling this disease on Advent tulips.
Disease pressure was high during these trials.
Virtually all of the plants in the check plots were killed prior to emergence.
All of the treatments significantly increased the number of plants that emerged.
Applications of Medallion (0.093-0.186 g a.i./m) and the higher rates of Moncut (0.260-0.521 g a.i./m) were as effective as Terraclor (3.345 g a.i./m). All of the fungicides except Heritage (0.093 g a.i./m) increased the number of marketable flowers.
Terraclor, Moncut (particularly the higher rates), and Medallion treatments also resulted in the highest number and weights of harvested bulbs.
In a trial to examine the crop safety of Moncut, in-furrow applications of this material at 0.521 g a.i./m of row had no adverse effects on the growth and yield of Advent, Leen VD Mark and Il de France tulips.
The results of these trials indicate that Moncut at 0.260 to 0.521 g a.i./m and Medallion at 0.093 to 0.186 g a.i./m of row have the potential to provide control of gray bulb rot on tulips that is equal to that achieved with Terraclor at 3.345 g a.i./m of row.
When bulbs are planted in infested soil, infected plants often fail to emerge or die shortly after emergence, resulting in the formation of missing or dead patches of plants in the field.
In-furrow applications of Terraclor (PCNB) are applied to most tulips at the time of planting in the Pacific Northwest to control this disease.
During the past several years, a series of replicated field trials have been conducted to compare the efficacy of in-furrow applications of Heritage 50WG (azoxystrobin), Medallion 50WP (fludioxonil), and Moncut 70DF (flutolonil) to Terraclor 75WP in controlling this disease on Advent tulips.
Disease pressure was high during these trials.
Virtually all of the plants in the check plots were killed prior to emergence.
All of the treatments significantly increased the number of plants that emerged.
Applications of Medallion (0.093-0.186 g a.i./m) and the higher rates of Moncut (0.260-0.521 g a.i./m) were as effective as Terraclor (3.345 g a.i./m). All of the fungicides except Heritage (0.093 g a.i./m) increased the number of marketable flowers.
Terraclor, Moncut (particularly the higher rates), and Medallion treatments also resulted in the highest number and weights of harvested bulbs.
In a trial to examine the crop safety of Moncut, in-furrow applications of this material at 0.521 g a.i./m of row had no adverse effects on the growth and yield of Advent, Leen VD Mark and Il de France tulips.
The results of these trials indicate that Moncut at 0.260 to 0.521 g a.i./m and Medallion at 0.093 to 0.186 g a.i./m of row have the potential to provide control of gray bulb rot on tulips that is equal to that achieved with Terraclor at 3.345 g a.i./m of row.
Authors
G. Chastagner, A. DeBauw
Keywords
fludioxonil, flutolonil, azoxystrobin, Rhizoctonia tuliparum, R. solani
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