Leveillula taurica is an important plant pathogenic fungus that causes powdery mildew. It prefers warm, dry environments. L. taurica exhibits white, fluffy spots on the bottom sides of leaves that spread and cause yellow spots on top. This leads to leaf loss, reducing fruit growth. L. taurica has a complex life cycle involving mycelium, conidia for asexual reproduction, and overwintering chasmothecia. It infects many plants like tomatoes, onions, and peppers. Management involves contact fungicides like potassium bicarbonate or neem oil.

1. COLLEGE OF AGRICULTURAL TECHNOLOGY
Affiliated to Tamil Nadu Agricultural University, Coimbatore
Kullapuram, Via Vaigai dam, Theni-625 562
Symptoms, host range, taxonomy and life cycle of
Leveillula
STUDENT COURSE TEACHER
Miss. SHIVASHINI. R Dr. PARTHASARATHY. S
ID. No. 2017021065 Asst. Prof., (Plant Pathology)

2. INTRODUCTION:
• Among various Leveillula sp., Leveillula
taurica is the most important plant pathogen
that causes powdery mildew of some species.
• This powdery mildew disease prefers warm,
dry environment.
• This pathogen causes Oidiopsis type of
powdery mildew.
• Its teleomorph is Oidiopsis taurica.

3. Leveillula taurica

4. S
SYMPTOMS OF POWDERY MILDEW BY
Leveillula taurica
• The leaf blade is the most affected organ.
• Symptoms appears on both ventral and dorsal
side of the leaf blade.
• Early symptoms-Bottom side of the leaf as
whithish spots that gradually expand and look
“fluffy”.

5. • As the disease symptoms progress, the top side
of the leaves will exhibit yellowish spots
corresponding to the bottom leaf spots.
• Extensive leaf shedding is caused due to
Leveillula taurica.
• Leaf loss leads to poor fruit growth and
exposes fruit to the sun, increasing potential to
sun scorch.

6. SYMPTOMSj
SYMPTOMS IN CHILLI SYMPTOMS IN ONION

7. SYSTEMATIC POSITION:
Kingdom : Fungi
Phylum : Ascomycota
Class : Leotiomycetes
Subclass : Leotiomycetidae
Order : Erysiphales
Family : Erysiphaceae
Genus : Leveillula
Species : Leveillula taurica

8. FUNGAL CHARACTERS OF
Leivellula taurica:
• It is an Oidiopsis type of fungi.
Mycelium:
• Mycelium is found on both intracellular and
extracellular.
• Mycelium is endophytic, branched, septate.
Asexual Reproduction:
• Haustoria: Present in epidermis and spongy
cells.

9. • Conidiophore:
Hyaline, long branched septate.
• Conidium:
Single celled, hyaline, clavate shaped
[club shaped].
• Conidiophores emerge through stomata in
clusters bearing a single conidium at the tip.
Sexual Reproduction:
• Chasmothecium:
They are black with myceloid
appendages.

10. • At the end of the growing season, powdery
mildew fungi produce sexual spores called
ascospores in a sac like ascus enclosed in a
fruiting body called chasmothecium.
• Each chasmothecium contains 8-12 ovoid asci
with basally arranged ascospores.

11. HOST RANGE
HOST RANGE:
• Leveillula taurica can infect many different
plants, it is actually very host specific.
• Different races of Leveillula taurica can infect
certain crops and even specific cultivars within
the same crop.
• An accurate way to express its host specificity
is that “a composite species consisting of many
host-specific races”.

12. • The most familiar families in agriculture which
are infected by Leveillula taurica are
Solanaceae, Cucurbitaceae, Brassicaceae,
Leguminaceae and Asteraceae.
• Some of the host plants of Leveillula taurica
are tomato, onion, chilli, castor, cluster bean,
red gram, brinjal, etc.,

13. MICROSCOPIC VIEW:
1] Infected leaf of Onion.
2] Internal mycelium
growing among
mesophyll cells.
3] Conidiophores
emerging from stomata.
4] Short chain consist of
primary conidium
subtended by secondary
conidium and immature
conidium (arrow).

14. 5] Primary conidium
germinating near apex.
6] Two primary
(pyriform or boat shape)
and four secondary
(cylindrical or elliptical
shape).
7] Branched
conidiophore.

15. 8] Detail of secondary
conidium showing reticulate
folds and minute wart- like
punctuations.
9] Conidial secession scar at
the end of secondary
conidium.
10] Chasmothecia
surrounded by hyphae.
11] Ascus with two
ascospores.
12] Ascospores.

16. LIFE CYCLE OF Leveillula taurica:
• The polycyclic disease cycle of Leveillula
taurica is similar to that of other powdery
mildew species.
• It spends the winter as chasmothecia in crop
residues above the soil surface.
• Under favourable climatic conditions, the
chasmothecia open and releases ascospores,
which are wind-dispersed.

17. • The ascospores enter the host through the
stomata, germinate and colonize the host’s
tissues with its mycelia.
• The pathogen then begins to produce its
asexual conidia, either singly or on branched
conidiophores.
• The conidia exit through the host’s stomata
and serve as a secondary inoculum to spread
disease after initial infection.

18. • In the unfavourable conditions, the pathogen
undergoes sexual reproduction and again
produces chasmothecia, its dormant
[overwintering] structure.

19. MANAGEMENT:
• Potassium bicarbonate is a contact fungicide
which kills the powdery mildew spores
quickly.
• In addition, it is approved in organic growing.
• Neem oil can also be used.

20. REFERENCES:
• Aneja K R, Mehrotra R S, 2015. An
Introduction to Mycology – (2nd edition). New
age International Publishers.
• Dude H C, 2013.An Introduction to Fungi –
(4th edition). Scientific Publishers.
• Alexopoulos C J, Mims C W, Blackwell M,
2014. Introductory Mycology – (4th edition) .
Wiley India Pvt. Ltd.,