Practical 5: Higher Fungi - Taxonomy and Pathological Importance (Phylum Ascomycota)

OBJECTIVE

1.      To identify the symptoms show in a plant disease.

INTRODUCTION

The phylum Ascomycota is a well develop fungi where all of the class are producing hyphae that are that consist of septate accept the class Hemiascomycetes . Most of them are identified based on the type of conidium that they produced. They may be openly attached on conidiospores, or are contained within fruiting body structure. There are several type of fruiting body or also known as ascocarps which are perithecium (closed with ostiole), apothecium (saucer shape),cleisthithecium (close and rounded) , ascostroma (cushioned shape with locules) and other.The ascocarps contain ascus bearing the ascospores (for sexual spores) that are usually 8 in number.

Activity :

A) Fungal culture

Penicillium sp.

Chaetomium sp.

Fusarium sp.

Curvularia sp.

B) Plant disease.

Powdery mildew of rubber Causal agent : Oidium heveae Symptoms : Infected leaves covered with white to gray powdery growth.	False smut of paddy   Causal agent : Ustilaginoidea virens Symptoms : The fungi form a ball-like shape where the color will change from orange, yellow, greenish-yellow and dark green.
Citrus scab Causal agent : Elsinoe fawcetti Symptoms : The attack often on the younger leaves and it will form a corky spot. The leaves will curled and the growth will stunted.	Leaf blight of corn Causal agent : Drechslera maydis Symptoms : Spot on the leaves. Light brown lesion.
Sigatoka disease of banana Causal agent : Mycosphaerella musicola Symptoms : Yellow line on leaves that will turn into brown after some time.	Moldy rot of rubber Causal agent : Ceratocyctis fimbriata Symptoms : The appearance of dull spot that will spread and will form uneven bend.
South American Leaf Blight (SALB) of rubber Causal agent : Mycrocyclus ulei Symptoms : On younger leaves there are greyish green spot under the leaves. After the leaves old the spot will be visible at the side of the leaves.	Sooty mould disease Causal agent : Tripospermum sp.  , Capnodium sp.  , Limacinula sp. Symptoms : A layer of black fungus will form which can be stripped from the leaves.
Black mildew Causal agent : Meliola sp. Symptoms : A layer of black fungus form on the leaves.	Blast of paddy Causal agent : Pyricularia oryzae Symptoms : Spot on leaves where is the color of the centre are whitish or greyish and surrounded by brownish color.
Brown spot of paddy Causal agent : Drechslera oryzae Symptoms : Brownish spot on leaves with greyish or whitish color on the centre.	Narrow brown leaf spot of paddy Causal agent : Cercospora oryzae Symptoms : 2-10 mm long and 1mm wide of brownish spot on leaves.
Sheath blight of paddy Causal agent : Rhizoctania solani Symptoms : Greyish green spot on the leaves with 1cm long and surrounded by whitish grey color.	Foot rot Causal agent :Sclerotium rolfsii Symptoms : Sudden wilting of individual plant. The discoloration of leaves to yellow. White mats of fungal growth growing on the stem and nearby the soil.
Anthracnose of chilli Causal agent : Collectotrichum capsici Symptoms : Lesion on mature fruit. There are formation of black acervulus at the centre of the lesion.	Anthracnose of mango Causal agent : Collectotrichum                      Gloeosporioides Symptoms : New leaf shoot become black and fall and leave the petiole. Leaf spot on older leaves. Yellow halo surrounding the spot.
Bird eye spot of rubber Causal agent : Drechslera heveae Symptoms : The leaves are fall. Circle spot on leaves and the center of the spot is transparent surround by brownish color.	Panama disease or banana wilt Causal agent : Fusarium oxysporum Symptoms : The leaves of the tree become yellow. The centre of the stem shown black strip. The infected part become rotten and smelly.