Characterization of Phytophthora spp. Isolated from Ornamental Plants in Florida

Abstract

This report investigates population structure and genetic variability of Phytophthora spp. isolated from botanically diverse plants in Florida. Internal transcribed spacer-based molecular phylogenetic analyses indicate that Phytophthora isolates recovered from ornamental plants in Florida represent a genetically diverse population and that a majority of the isolates belong to Phytophthora nicotianae (73.2%), P. palmivora (18.7%), P. tropicalis (4.9%), P. katsurae (2.4%), and P. cinnamomi (0.8%). Mating type analyses revealed that most isolates were heterothallic, consisting of both mating type A1 (25.2%) and mating type A2 (39.0%), and suggesting that they could outcross. Fungicide sensitivity assays determined that several isolates were moderate to completely insensitive to mefenoxam. In addition, several isolates were also moderately insensitive to additional fungicides with different modes of action. However, correlation analyses did not reveal occurrence of fungicide cross-resistance. These studies suggest that a genetically diverse Phytophthora population infects ornamental crops and the occurrence of mefenoxam-insensitive Phytophthora populations raises concerns about disease management in ornamentals. Mitigating fungicide resistance will require prudent management strategies, including tank mixes and rotation of chemicals with different modes of actions.

Usage of pharmaceutical contraceptive drug for controlling Eobania vermiculata snails by baits technique

“…There was a marked increase in the size of the ovotestis number of oocytes in Achatina fulica snails injected with estradiol and progesterone ( Kruatrachue et al., 1996 ). Chitosan and emamectin benzoate caused prevention of egg production in treated E. vermiculata snails ( Patel et al., 2016 ; Kandil et al., 2020 ). Finally, the squeaky decreases of the tested reproductive hormones levels, malformations of sperms and ova and complete egg cessation at the third week after treatment of snails with contraceptive pills as baits may assure the efficacy of this method in controlling high population densities of E. vermiculata devouring citrus trees at Sharkia Governorate, Egypt.…”

A High Incidence of Pythium and Phytophthora Diseases Related to Record-breaking Rainfall in South Florida

“…In the present study, diseases caused by Phytophthora were more common than Pythium in ornamental nursery crops, which is of great relevance due to the potential of Phytophthora as an important pathogen in a wide range of ornamental crops (Erwin and Ribeiro, 1996;Patel et al, 2016).…”

“…Phytophthora has been previously reported as one of the most common and damaging pathogens associated with ornamental plant production in Florida (Patel et al, 2016).…”

“…Mandevilla is one of the common ornamental plants produced in south Florida and remains highly susceptible to Phytophthora. In fact, a recent publication focusing on Phytophthora species affecting ornamentals in Florida indicated mandevilla is susceptible to both Phytophthora palmivora and Phytophthora nicotianae (Patel et al, 2016). In addition to the hosts listed in Table 5, new diseases reported in south Florida include a foliar blight of the zz plant (Zamioculcas zamiifolia) and 'Petra' croton (Codiaeum variegatum) caused by P. nicotianae, and a root and basal rot of echeveria (Echeveria sp.)…”

Bioactivity-driven high throughput screening of microbiomes of medicinal plants for discovering new biological control agents

“…Phytophthora parasitica, which infects a variety of ornamental, vegetable and citrus [22] was used as target plant pathogen for evaluating the antimicrobial activity of the recovered bacterial endophytes. Dual-culture growth inhibition assays were conducted in petri dishes as follows:A 0.5 cm diameter mycelial plug from 5 days old P. parasitica culture was placed in the middle of V8 medium, and incubated for 48 h at 25°C.…”