Philippine downy mildew - Peronosclerospora philippinensis
EEffective: August 18, 2010 - December 31, 2019
Taxonomic Position:
Sclerosporales : Sclerosporaceae
Pest Type:
Fungi
Pest Code (NAPIS):
FFABPMF
This pest is a member of the following lists:
These Approved Methods are appropriate for:
2020, 2019, 2018, 2017, 2016, 2015
Major Hosts identified in the Host Matrix:
Corn; Sugarcane
This list includes important economic or environmental hosts but does not represent all major hosts of the pest. Check CAPS pest datasheet for complete list of hosts.
Pest is vectored by:
No known vector.
Survey
Approved Method(s):
Method |
Instructions |
NAPIS Survey Method |
Visual |
Collect symptomatic plants. Unsprayed, susceptible plants (sentinel plots) that are scouted regularly can be used for early detection. |
3031 - General Visual Observation
|
Signs:
Downy (grayish) fungal structures are observed primarily on the underside of the leaves.
Symptoms:
Chlorotic stripes/streaks are usually the first symptom observed. As the plant ages, leaves may narrow, become abnormally erect, and appear somewhat dried-out. As the corn plant matures, tassels become malformed and produce less pollen, ear formation is interrupted, and sterility of seeds can result.
There is a synergistic relationship between downy mildew fungi and maize streak virus (MSV) on corn. Infection by MSV can mask symptoms of downy mildew infection.
Key Diagnostics
ID/Diagnostic: Morphological
1. Morphological: condiophore structure and dimension and spore (conidia) shape and size (Smith and Renfro, 1999).
2. Isozymes: comparisons have been used to identify Peronosclerospora spp., including P. maydis (Bonde et al., 1984; Micales et al., 1988).
Mistaken Identities:
Peronosclerospora spp. and other downy mildew genera (including Sclerospora and Scleropthora).P. philippinensis is indistinguishable from P. sacchari by isozyme analysis and many experts have synomized the two species.
In Progress / Literature-based Diagnostics:
Molecular: Some DNA-based approaches have been reported for other Peronosclerospora spp., which indicates that a molecular method for identification may be available in the future.
Yao et al. (1991a) created a DNA clone that could be used as a species-specific hybridization probe for the detection and identification of P. sorghi.
Yao et al. (1991b) then developed a DNA probe from a P. maydis genomic library to detect P. sacchari in corn leaves and seeds.
Ladhalakshmi et al. (2009) used a DNA sequence characterized amplified region (SCAR) marker for identification of isolates of P. sorghi from corn using PCR.
There has been some work on SSR markers for P. sorghi and related species that include this pathogen and will be helpful for identification and future PCR primer development (Perumal et al., 2008).
Notes:
Peronosclerospora philippinensis is on the
Select Agent List.