Efficient Control of Apple Scab with Targeted Spray Applications

Abstract

For two consecutive growing seasons (2017 and 2018), three different fungicide spray programs, each with five sprays from unrelated chemical groups, were evaluated for their effectiveness against apple scab (causal agent: Venturia inaequalis) in an experimental trial in Greece. The targeted application programs consisted of five sprays with protective and systemic fungicides from unrelated chemical groups, in alternation. The applications were started at the pink bud stage (a copper-based fungicide had previously been applied at the green bud stage) and completed at the second fruit fall to arrest the primary infections by ascospores. These five-spray programs were compared to the standard farmer practice (12 sprays per season), whereas untreated plots were used as controls. The timing of the applications was based: a) on the critical growth stage of the crop, and b) on the risk analysis for infection calculated by the software Field Climate, which incorporated meteorological data from the trial site. All the five-spray programs were of very high efficacy against apple scab, showing disease severity ratings on leaves and fruits below 1.88%. In both years, in the untreated control, the disease incidence and severity on leaves ranged from 96.5% to 99.3% and from 65.2% to 75.93%, respectively. The five-spray programs showed similar efficacy to the standard 12-application program in all cases. From the results, it becomes apparent that apple scab can be controlled effectively by five targeted applications with selected fungicides at critical growth stages of the crop.

Bacterial Endophyte Community Dynamics in Apple (Malus domestica Borkh.) Germplasm and Their Evaluation for Scab Management Strategies

“…In the Jammu and Kashmir state, this disease was reported in 1970s and ever since, it has caused havoc in the apple industry with the extent of fruit loss of up to 60%, estimating an amount in hundreds of crores [4]. V. inequalis, being a heterothallic haploid ascomycete, reproduces both sexually and asexually [3][4][5][6]. The disease takes the severe form in regions in which recurrent rainfall through the spring seasons leads into ascospore emancipation and infection [5].…”

“…It shall be noted that some limited research studies have managed to contain the disease by spraying only five chemical-based fungicidal compounds at critical growth stages of the crop [4,5]. Systemic fungicide sprays limited to seven in number have previously been able to contain the disease but due to the emergence of fungicide resistance in pathogens, these practices have become obsolete [6]. A recent survey in southeastern Europe has revealed the development of resistance in V. inaequalis against the potent fungicides dodine, pyraclostrobin, boscalid, difenoconazole, and cypradonil [11].…”

Management of premature leaf fall (Marssonina coronaria) of apple with new generation fungicides in the North‐Western Himalayan Region of India

“…The other chemicals (mancozeb, metiram+pyraclostrobin) used in the present study had previously been reported to have good efficacy against PLF (Kumar & Sharma, 2014). Earlier studies also demonstrated the efficacy of tebuconazole +trifloxystrobin against scab disease of apple (Chatzidimopoulos et al, 2020), of fluxapyroxad+pyraclostrobin against powdery mildew disease of mango (Ravikumar et al, 2018) and of fluopyram+tebuconazole against PLF disease of apple (Verma & Khosla, 2018).…”

Crop Rotation Enhances Agricultural Sustainability: From an Empirical Evaluation of Eco-Economic Benefits in Rice Production

“…Up to 15 fungicide sprays are executed annually to control potato late blight in Northern and Western Europe [5] and more than 20 fungicide sprays are applied to control rose mildew in some parts of the world [6]. In apple, more than 12 fungicide applications usually take place each season to control scab caused by Venturia inaequalis [7], even though a recent result indicated that only five applications could achieve the similar control purpose [8]. High resource inputs may usually increase gross production of crops but many of them may not generate positive net returns due to the gain in production being over-weighted by excess inputs.…”