The Use of Film-Forming Polymers to Control Guignardia Leaf Blotch and Powdery Mildew on Aesculus hippocastanum L. and Quercus robur L.

Abstract

The effects of four commercially available film-forming polymers (Bond, Designer, Spray Gard, Nu-Film-P) on disease severity of powdery mildew (Microsphaera alphitoides Griffon and Maubl.) on English oak (Quercus robur L.) and Guignardia leaf blotch (Guignardia aesculi (Peck) Stewart) on horsechestnut (Aesculus hippocastanum L.) were examined in a field experiment. In addition, a comparative evaluation of the fungicide penconazole, commercially used for powdery mildew control, was conducted. Effects on tree vitality were also assessed by measuring leaf chlorophyll fluorescence and chlorophyll concentrations. Irrespective of tree species, Nu-Film-P and Spray Gard did not significantly influence disease severity of powdery mildew and Guignardia leaf blotch. Likewise, no significant effects of these two film-forming polymers on chlorophyll fluorescence and chlorophyll content were recorded. Reduction in disease severity following spray applications of the film-forming polymers Bond and Designer was statistically comparable with penconazole. None of the film-forming polymers and fungicide evaluated was phytotoxic to the test trees. Results suggest that application of an appropriate film-forming polymer may provide a useful addition to existing methods of plant disease control.

Boxwood phyllosphere fungal and bacterial communities and their differential responses to film-forming anti-desiccants

“…Sutherland and Walters [ 46 ] also reported three anti-desiccants changed the morphology of the appressoria and haustoria in Blumeria graminis . Some anti-desiccants also suppressed powdery mildew [ 32 , 46 ], grey mold [ 33 ], leaf rust [ 47 ], and Guignardia leaf blotch [ 20 ]. Compared with fungi, bacteria on the plant surface can produce biofilm, a matrix of extracellular polymeric substances to provide adequate protection and mitigate environmental stresses [ 48 – 50 ].…”

“…Most importantly, he provided electron microscopic evidence to show that kaolin anti-desiccant inhibited spore germination and disrupted the sporangia formation of the casual pathogen Pseudoperonospora cubensis [ 19 ]. The controlling effect of anti-desiccants on many other foliar diseases was also reported for various plants [ 20 , 33 – 35 ]. These studies together imply that the film-forming anti-desiccants may direct or indirectly act against fungi with unclear mechanisms.…”

Rainfastness of Poly(vinyl alcohol) Deposits on Vicia faba Leaf Surfaces: From Laboratory-Scale Washing to Simulated Rain

“…The chemistry of Nu Film is based on polymeric terpenesnaturally occurring organic molecules and polymers and their derivativeswhich are film forming. Polymers that form films after application are common, and this seems to be the mode of action for much of the adjuvancy exhibited by polymeric formulations. , …”

“…Polymers that form films after application are common, and this seems to be the mode of action for much of the adjuvancy exhibited by polymeric formulations. 31,32 Many studies have examined the retention of liquid formulations as they impact a leaf surface or as a liquid droplet on the surface. 33−36 Prior work has also provided several methods for determining the impact of simulated rain on pesticide deposits, such as copper-based fungicides.…”