MaxwellHandiseniPLPA631

UNKNOWN FUNGI PROJECT

Sclerotinia spp

Introduction

Sclerotinia disease also known as white mould affect a wide range of crops. Losses ranging from negligible to 100% has been reported in literature. Crops that are affected by Sclerotinia spp include bean, eggplant, lettuce, peanut, potato, soybean and sunflower. White mould is a soil borne disease.

Materials and methods

Voluntary young pumpkin plants with whitish mold on their base stem from the back yard of my apartment were collected. The samples were washed in running water and then cut into small pieces. The small pieces were then divided into two portions. The first porting was plated directly on 1/5 PDA plates and the second portion was immersed in 30% alcohol solution for 1 minute followed by thorough washing using running water and then plated on 1/5 PDA plates. The plates were incubated for 72 hours at 25C. The samples were checked daily for fungal growth. Using a sterilized scarpel hyphal tips of any growing fungi were subcultered into a fresh 1/5 PDA plates. The subcultered samples were then examined using microscopy techniques for any structures that could be used to identify the unknown fungi.

Results

By looking at the symptoms and signs on the plant I had suspected that the unknown pathogen was probably a Sclerotinia spp. Hyphal properties such as the branching and production of sclerotia confirmed my suspicion that the unknown species was a Sclerotinia spp.

White mould like structures on pumpkin seedling stems

Sclerotinia forming sclerotia

Sclerotia spp hypha branching

Conclusions

I can conclude that the unknown fungi were probably a Sclerotinia spp based on the signs and symptoms, on the plant, hyphal characteristics and production of sclerotia. However additional identification of structures such as apothecium which I did not observe in this species would have confirmed with no doubt that the unknown species was indeed a Sclerotinia with all certainty.

Cervularia spp

Introduction

Cuvularia spp., are darkly pigmented fungi with spores (conidia) efficiently adapted for aerial dissemination. It has very distinctive and beautiful spores, which can be easily identified in both spore traps and direct exams. The shape of the spore is so distinct that it's name came from its shape.

Materials and methods

Leaves from an ornamental palm plant with leaf spots were collected from a flower bed near the Plant Pathology greenhouses. The samples were washed in running water and then cut into small pieces. The small pieces were then divided into two portions. The first porting was plated directly on 1/5 PDA plates and the second portion was immersed in 30% alcohol solution for 1 minute followed by thorough washing using running water and then plated on 1/5 PDA plates. The plates were incubated for 72 hours at 25C. The samples were checked daily for fungal growth. Using a sterilized scarpel hyphal tips of any growing fungi were subcultered into a fresh 1/5 PDA plates. The subcultered samples were then examined using microscopy techniques for any structures that could be used to identify the unknown fungi.

Results

Microscopically, the spore appears boomerang shaped to more or less spindle shaped and bent. The spores are smooth walled with 3-4 true transverse septa resulting multi celled spores. Macroscopically, colonies on agar media appear black, hairy and expanding.

Leaf spots on ornamental palm plant

Curvularia spp on PDA 48 hours after incubation

Curvularia spp on PDA 7 days after incubation

Cervularia spores

Conclusions

I concluded that the isolated fungi from ornamental palm plant was Cervularia spp

Colletotrichum spp

Introduction

Colletotrichum is one of the most important plant pathogens worldwide causing the economically important disease anthracnose in a wide range of hosts including cereals, legumes, vegetables, perennial crops and tree fruits. Among these hosts, chilli (Capsicum spp.), an important economic crop worldwide, is severely infected by anthracnose which may cause yield losses of up to 50%. Typical anthracnose symptoms on chilli fruit include sunken necrotic tissues, with concentric rings.

Materials and methods

Chilli fruits were collected from the Department of Horticulture Organic garden on west campus. The fruits exhibited typical anthracnose caused by Colletotrichum spp. The samples were washed in running water and then cut into small pieces. The small pieces were then divided into two portions. The first porting was plated directly on 1/5 PDA plates and the second portion was immersed in 30% alcohol solution for 1 minute followed by thorough washing using running water and then plated on 1/5 PDA plates. The plates were incubated for 72 hours at 25C. The samples were checked daily for fungal growth. The samples immersed in 30% alcohol were had few other fungi growing such that the plates were directly examined using microscopy techniques for any structures that could be used to identify the unknown fungi.

Results

Based on the symptoms and signs on the chilli fruit I suspected that the causative pathogen was a Colletotrichum spp. Microscopy analysis resulted in the observation of conidia and conidiogenous cells.