Comparative in vivo and in vitro study on Monilia fructicola causing brown rot of stone fruit in Brazil and California

Abstract

Stone fruit production plays an important economical role in southern Brazil as well as in California, United States. In both countries, brown rot caused by Monilinia fructicola is the most important stone fruit disease, responsible for significant pre-and post-harvest fruit losses. The United States is among the main importers of stone fruit to Brazil. Imported fruit carrying the pathogen may introduce isolates with greater ability to infect stone fruit orchards in Brazil. In this study, 26 M. fructicola isolates from Brazil and California, recovered from commercial stone fruit orchards, were randomly selected and compared based on in vitro (optimum growth temperature, mycelial growth rate, germination, spore production and germ tube rate) and in vivo (sporulation, area under disease progress curve, incubation and latent period) studies on brown rot infection components. The isolates behaved similarly for most of the studied variables, except for germ tube length and sporulation on fruit, which were higher in isolates from California and Brazil, respectively. The negative correlation between these variables may be disadvantage for isolates from California to cause infections in the main peach cultivar grown in South Brazil. Significant differences in incubation and latent period and the area under disease progress curve were found among isolates from a same country. Such differences may be due to intraspecific diversity associated with the occurrence of the perfect stage in California, and by the broad sampling area from where isolates from Brazil were obtained. It is still difficult to determine the effect of isolates arising from imported California fruits in Brazilian stone fruit orchards. Further genetic variability studies and comparative epidemiology in the field may help to understant the real threat that foreign isolates represent.

Characterization of Monilinia species associated with brown rot in stone fruit in Brazil

“…Lichtemberg et al . () observed differences between isolates from Brazil and California through analysis of germ tube length and sporulation, which highlights the necessity of genetic variability studies to better understand the epidemiology of this disease, including the impact of introducing foreign strains, and to develop strategies to control the disease.…”

Kinetic parameters related to nitrogen uptake in ‘Okinawa’ peach rootstocks are altered by ‘Chimarrita’ scion Nitrogen uptake in ‘Okinawa’ peach rootstock

“…Thus, it is expected that with the grafting of scion cultivars, the root system of the rootstock will absorb water and nutrients in correspondence with the needs of the graft. The ‘Chimarrita’ scion originated from the Brazilian peach breeding program of Embrapa (1978) 15 and is mainly used for peach production destined for market consumption in several countries 16‐18 …”

“…The 'Chimarrita' scion originated from the Brazilian peach breeding program of Embrapa (1978) 15 and is mainly used for peach production destined for market consumption in several countries. [16][17][18] Considering N, the mechanisms that trigger the nutrient uptake by roots are initiated through biochemical signals from the plant's aerial part. 19 At the leaf level, CO 2 absorption capacity is determined by the N allocated in processes associated with light absorption, electron transport, and carboxylation.…”

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) in Peaches: is it a problem?

“…For example, natural field infestation of D. suzukii in grapes is low when there are only undamaged, healthy grapes; however, field infestation increases when the grapes have natural mechanical damage or diseases (Ioriatti et al, 2015). Peaches also incur fruit damage, from various agents including arthropod pests such as fruit flies or Nitidulidae beetles, fungi such as Monilinia fructicola Honey, causing the brown rot disease (the most important in Brazil (Lichtemberg et al, 2016)), birds, or weather events such as hail. Here, we evaluated the interaction between D. suzukii infestation and different types of field damages to peaches.…”