Preliminary Studies on Fungal Species Associated with Guava Fruit Drop Disease and Possible Management

Abstract

our phytopathogenic fungi, i.e. Alternaria alternata, Lasiodiplodia theobromae, Fusarium semitectum and Pestalotia psidii, were isolated from the dropped guava fruits collected from different orchards located at Beheira Governorate during 2013 and 2014 growing seasons. Disease incidence recorded higher percentages during 2013 than that of 2014 season. Pathogenicity of the isolated fungi was carried out on apparently healthy guava fruits, attached to its branches, collected from 15-year-old trees. Data show that maximum disease intensity was occurred on either petioles and/or fruits inoculated with mixture of fungal pathogens. These results indict that guava fruit drop might be a fungal disease complex when caused by certain phytopathogenic fungi. Four fungicides, i.e. Kemazed, Homai, Vacomil plus and Topas, were in vitro evaluated for their efficacies against the isolated pathogenic fungi. Moreover, the efficacy of four compounds, i.e. hydrogen peroxide, potassium sorbate, potassium bicarbonate and calcium chelate, was in vitro evaluated as alternative control means against the growth of tested pathogenic fungi. In this concern, hydrogen peroxide and potassium bicarbonate recorded the highest performance against the tested fungi. Under natural field infection, chemical control trails cleared that the efficiency of Homai 80% WP and Kemazed 50% WP reached 69.0 and 78.8%, respectively, as compared to the check treatment. It is worth to note that the concerned disease could be controlled by applying either of Homai 80% or Kemazed 50% at the rate of 70 g/100 l water.

Premature Apple Fruit Drop: Associated Fungal Species and Attempted Management Solutions

“…Furthermore, A. alternata, Pleospora herbarum, Coniothyrium spp., Penicillium funiculosum, P. expansum, and P. ramulosum were associated with core rot of 'Starking Delicious' apple fruit in South Africa [22,23]. In a previous study, four phytopathogenic fungi, A. alternata, Lasiodiplodia theobromae, F. semitectum, and Pestalotia psidii, were isolated from dropped guava fruit samples collected from different orchards [15].…”

“…Strategies to reduce PAFD can help preserve crop yield, which is an essential factor for the economic success of an orchard [29]. In this context, a previous study showed that guava fruit drop could be controlled by applying either thiophanate methyl 50% + thiram 30% or carbendazim (50% WP) at aproportionof 70 g•100 L −1 water [15]. The successful control of a disease is dependent on the reliability of pathogen detection at a latent phase [30].…”

“…The same concentration of 10 6 spores•mL −1 was used for the mixed infection. Inoculation was done according to Youssef et al [15], by injecting either fruit petioles or fruit with 50 µL of the spore suspension. A set of petioles and control fruit were injected with sterilized water only.…”

“…The fungicides were applied by spraying the recommended dose at the beginning of fruit set on a private farm on the Cairo-Alexandria desert road (Giza Governorate), Egypt. Set fruits were counted before the fungicide application [15]. The orchards were divided into a randomized complete block design.…”

Effect of Hyacinth Treatment by Hydrogen Peroxide Stabilized with Silver and Some Fungicides on the Fungal Infection of Substrate and Bulbs and on Plant Growth and Development

“…and P. italicum Wehmer isolates obtained from strawberry and orange. Additionally, hydrogen peroxide in vitro showed a high efficacy in limiting the growth of Pestalotia psidii Pat., a fungus isolated from guava fruit [15].…”