Suppression of cucumber powdery mildew (Sphaerotheca fuliginea) by foliar sprays of pbospbate and potassium salts

Abstract

Powdery mildew, caused by Sphaerotheca fuliginea, was significantly controlled by a single spray of aqueous solutions (25 mm) containing various phosphates and potassium salts. Phosphates were suppressive when applied alone; however, treatments in combination with Tween‐20 were more effective in causing the disappearance of powdery mildew pustules from diseased foliage. Efficiency of control, as expressed by the disappearance of 99% of pustules, was recorded 1 or 2 days after application of single sprays of phosphate and potassium salt solutions. Treatment was effective for up to 12 or 15 days, respectively, following application to small or large greenhouse‐grown plants with established mildew infection. Treatments also markedly reduced (> 99%) the production of eonidia from colonies. A further application of these salts to the same plants resulted in the elimination of about 50% of mildew colonies present prior to the application. Further spray application inhibited disease development compared with water‐sprayed plants, but did not reduce the number of existing lesions. Phosphate was more effective than the systemic fungicide pyrifenox and reduced established powdery mildew infection up to 11 days after application, but the converse was true when assessments were made after 15 days. These properties of phosphates and potassium salts make them appropriate for use as foliar fertilizers with a potential beneficial influence on disease control.

Avaliação de produtos alternativos para controle da requeima do tomateiro

“…O leite possui diversos sais e aminoácidos que podem induzir resistência sistêmica (Reuveni et al, 1995;Pasini et al, 1997). Aparentemente, no presente trabalho, não houve indução de resistência a P. infestans nos tomateiros tratados com leite de vaca, nos quais a taxa de progresso da doença foi similar à das plantas da testemunha.…”

<i>In Vitro</i> Evaluation of Some Fungicides Alternatives Against <i>Fusarium Oxysporum</i> the Causal of Wilt Disease of Pepper (<i>Capsicum </i><i>a</i><i>nnum </i>L.)

“…Potassium salts (K 2 HPO 4 or KNO 3 ) as a chemical agent for induction of plant resistance had great attention in many of these reports [43,44]. Moreover, there has been considerable interest in the use of sodium bicarbonate and potassium bicarbonate for controlling various fungal diseases in plants [45][46][47].…”

Occurrence of Sclerotinia Foliage Blight Disease of Cucumber and Pepper Plants under Protected Cultivation System in Egypt II. Bio-Control Measures against Sclerotinia Spp. in Vitro

“…Potassium salts (K 2 HPO 4 or KNO 3 ) as a chemical agent for induction of plant resistance had great attention in many of these reports [4,5]. In this concern, spraying cucumber plants with K 2 HPO 4 induced resistance against downy and powdery mildews and increased fruit yield per plant under commercial greenhouse conditions [22,23,24,25,26]. Furthermore, there has been considerable interest in the use of sodium bicarbonate, potassium bicarbonate and potassium phosphate for controlling various fungal diseases in plants [22,23,27,28,29].…”

“…In this concern, spraying cucumber plants with K 2 HPO 4 induced resistance against downy and powdery mildews and increased fruit yield per plant under commercial greenhouse conditions [22,23,24,25,26]. Furthermore, there has been considerable interest in the use of sodium bicarbonate, potassium bicarbonate and potassium phosphate for controlling various fungal diseases in plants [22,23,27,28,29]. Spraying plants with either sodium bicarbonate or potassium bicarbonate solution provided good control of several plant diseases [26,29,30].…”