Evaluation of host resistance inducers and conventional products for fire blight management in loquat and quince

Abstract

Fire blight disease is one of the most destructive diseases of pome fruits. Due to the lack of effective, non-phytotoxic and publicly acceptable materials for controlling fire blight in pome fruit trees, new strategies to manage Erwinia amylovora fire blight are being sought. The resistance-inducing compounds prohexadione-Ca, harpin protein and benzothiadiazole (acibenzolar-S-methyl), the fertilizer humic acid, the bactericides streptomycin and copper salts, and combinations of copper with chemicals were evaluated for their ability to control fire blight on quince and loquat cultivars. Prohexadione-Ca was applied at a rate of 125 mg L-1 at two shoot lengths (6-12 cm and 15-20 cm), while benzothiadiazole + metalaxyl (135 mg L-1) and harpin (50 mg L-1) were applied when the shoots measured between 15-20 cm, and again at 30-35 cm. On loquat cv. Cukurgobek, benzothiadiazole + metalaxyl showed about 60% effectiveness. The addition of copper salts reduced the effectiveness of benzothiadiazole + metalaxyl. On quince cultivars, streptomycin (P ≤ 0.05) was the most effective treatment during both years, followed by the harpin protein alone and in combination with copper salts. Prohexadione-Ca, benzothiadiazole + metalaxyl, and harpin protein applications reduced disease severity on inoculated shoots compared with copper and untreated controls. Prohexadione-Ca reduced both shoot length and shoot blight on the two hosts. Humic acid applications were ineffective in controlling fire blight on loquat and quince cultivars. Quince cv. Eşme showed lower disease severity than cv. Ekmek (P ≤ 0.05). The use of resistance-inducing substances during the early phase of shoot growth may offer a means of managing the shoot blight phase of fire blight disease on quince and loquat.

Efficacy of different chemical and biological products in the control of Pseudomonas syringae pv. actinidiae on kiwifruit

“…In all the trials, the new formulate IRF 155 (copper oxychloride + copper hydroxide) was one of the most promising products for bacterial disease control, able to reduce the leaf disease symptoms by 70-80 %, compared with the control. Acibenzolar-S-methyl, a functional analogue of salicylic acid, has demonstrated good efficacy against bacterial diseases, including bacterial spot and bacterial speck on tomato (Louws et al 2001) and fire blight in apples (Bastas and Maden 2007). Similar efficacy was provided by acibenzolar-S-methyl against Psa on kiwifruit.…”

Levels of fire blight (Erwinia amylovora) susceptibility of native apple, pear and quince germplasm from Lake Van Basin, Turkey

“…It is known that orchard practices minimizing excessive vegetative growth of trees reduce host plant susceptibility to fire blight. Many growth regulators reducing shoot growth are also used to reduce fire blight intensity (Yoder et al 1999;Bastas and Maden 2007). Hepaksoy et al (1999) observed that fire blight damage progressed more on young and strongly growing shoots of pear trees, and thus these shoots were more susceptible to fire blight.…”

Elicitors: A Tool for Improving Fruit Phenolic Content

“…Harpin has been applied as an effective postharvest treatment to prevent decay in oranges [103], melons [104], apples [105] and pears [106]. In addition, field applications demonstrated its usefulness for controlling pathogen-borne diseases in passion fruits [107], pears [108], quince and loquat [109].…”