Quarantine Pests Associated with Seed of Corn 

Relatives in the Genera Echinochloa, Eleusine, 

Miscanthus, Panicum, Pennisetum, Setaria, and 

Tripsacum 

United States Department 

of Agriculture 

Animal and Plant Health 

Inspection Service 

November 2007 

Agency Contact: 

Plant Epidemiology and 

Risk Analysis Laboratory 

Center for Plant Health 

Science and Technology 

Plant Protection and 

Quarantine 

1730 Varsity Drive, 

Suite 300 

Raleigh, NC 27606 

 
Rev. Original July 18, 2008 2

Background 

This selected list of plant pests occurring on the seed of "corn relatives" was prepared by 

the Center for Plant Health Science and Technology (CPHST) of the United States 

Department of Agriculture (USDA), Animal and Plant Health Inspection Service 

(APHIS), Plant Protection and Quarantine (PPQ) at the request of Alan Green, Director 

of Plant Health Programs (PHP). The corn relatives in question are Echinochloa spp. 

(barnyardgrass), Eleusine spp. (finger millet), Miscanthus spp. (silver grass), Panicum

spp. (millet), Pennisetum spp. (pearl millet), Setaria spp. (foxtail millet), and Tripsacum 

spp. (gamagrass). This request was for a pest risk assessment that confirms at least one 

seedborne quarantine pest is associated with each of the seven genera. The IPPC (2006) 

defines a quarantine pest as “a pest of potential economic importance to the area 

endangered thereby and not yet present there, or present but not widely distributed and 

being officially controlled.” 

This request was for a science-based justification for the current prohibition on the 

importation of seeds of seven genera of corn relatives. This justification is needed for a 

proposed rule for consolidating the provisions of the 7 CFR 319 subparts that deal with 

plants for planting into the revised 7 CFR 319.37. PPQ prohibits the seeds of 

Echinochloa, Eleusine, Panicum, Pennisetum, and Setaria from areas including Africa, 

Australia, Brazil, Bulgaria, Japan and adjacent islands, Korea, New Zealand, Oceania, the 

People’s Republic of China, Southeast Asia, Taiwan, and the former Soviet Union 

(Helms, 1987). Similarly, PPQ port-of-entry manuals prohibit seeds of Miscanthus and 

Tripsacum from “specific countries listed in 319.24 and 41.” Except for two species of 

Pennisetum mentioned in 7 CFR 319.41, neither regulation names these genera. Because 

existing regulations do not specifically prohibit the seeds of these seven genera, PHP 

requested a risk-based justification for adding these prohibitions to 7 CFR 319.37. The 

expected products include a pest risk assessment that includes at least one quarantine pest 

for each regulated genus (Echinochloa, Eleusine, Miscanthus, Panicum, Pennisetum, 

Setaria, and Tripsacum) and a list of quarantine pests transmitted by seeds of the genus. 

This request is an important step in the revision of 7 CFR 319.37, which is a high priority 

for PPQ. It meets an immediate need to review the current administrative prohibitions in 

the Code of Federal Regulations (CFR, 2007a, 2007b) for seeds of these genera. 

Objective

The objective is to provide an annotated list of quarantine pests that are seedborne on the 

corn relatives Echinochloa, Eleusine, Miscanthus, Panicum, Pennisetum, Setaria, and 

Tripsacum. 

Seedborne versus Seed-Transmitted Pathogens

Seedborne pathogens are pathogens carried with, on, or in seeds. In contrast, seedtransmitted pathogens are not only seedborne, but also cause plant infection following 

seed propagation (Maude, 1996). Therefore, the pathogens listed in Table 1 may or may 

not cause direct infection of seed of the seven evaluated genera. In addition, they may or 

may not propagate on or in the seed, or cause infection in the plants growing from the 

seeds. 
Rev. Original November 16, 2007 3

Selected quarantine pests on corn relatives 

Each of the seven corn relatives (Table 2) has two or more seedborne pests that are of 

quarantine significance. The IPPC (2006) defines a quarantine pest as “a pest of potential 

economic importance to the area endangered thereby and not yet present there, or present 

but not widely distributed and being officially controlled.” 

Table 1. Selected seedborne pests listed by genera that are expected to be 

transmitted by seeds of corn relatives. 

Pest Scientific Name of Pathogen Present in 

U.S. 

Comments on the 

Pathway 

Distribution

Claviceps fusiformis Loveless 

[Fungi: Ascomycetes: Hypocreales: 

Clavicipitaceae] 

No 

(Wilson, 2000) 

Sclerotia can 

contaminate seed lots 

(Wilson, 2000). 

Asia, Africa 

(Wilson, 2000) 

Claviceps panicoidearum Tanda & 

Y. Harada [Fungi: Ascomycetes: 

Hypocreales: Clavicipitaceae] 

No 

(CABI, 2007) 

Sclerotia in other 

genera can contaminate 

seed lots 

(Wilson, 2000). 

Japan only 

(CABI, 2007; 

JSCC, 2007; 

Tsukiboshi, 

2001) 

Heterodera delvii Jairajpuri Khan, 

Setty & Govindu 

[Nematode: Heteroderidae] (Cereal 

cyst nematode) 

No 

(CABI, 2007) 

This cyst nematode is 

dispersed with soil 

debris and by plant 

material contaminated 

by the cysts 

(SON, 2003). 

India (CABI, 

2007; SON, 

2003) 

Heterodera sacchari Luc & Merni 

[Nematode: Heteroderidae] 

(Sugarcane cyst nematode) 

No 

 (CABI, 2007; 

SON, 2003) 

International transport 

may occur through soil 

or growing medium 

attached to plants or 

seeds 

(SON, 2003). 

Africa, Asia, 

Europe ( Farr et 

al., 2007 ,SON, 

2003) 

Peanut clump furovirus (PCV) 

[Virus] 

No 

 (Brunt et al., 

2006) 

Transmitted by seed 

(10%) in Setaria

 (Brunt et al., 2006). 

Africa, India 

(Brunt et al., 

2006) 

Peronosclerospora philippinensis

(W. Weston) C. G. Shaw Syn: 

Sclerospora philippinensis W. 

Weston [Chromista: Oomycetes: 

Sclerosporales: Sclerosporaceae] 

No 

(CABI, 2007) 

Seedborne transmission 

may occur in corn 

(CABI, 2007). 

Asia, Africa

CABI, 2007) 

Peronosclerospora sacchari (T. 

Miyake) Shirai & Hara 1927 

[Chromista: Oomycetes: 

Sclerosporales: Sclerosporaceae] 

No 

( Farr et al., 

2007, PNKTO, 

1986) 

Disseminated as a 

contaminant 

(PNKTO, 1986). 

Asia, Africa, 

Central 

America, 

Oceania South 

America

(including 

Brazil), (CABI, 

2007; SON, 

2003) 
Rev. Original July 18, 2008 4

Table 2. Selected quarantine pests2 on corn relatives3. 

Claviceps fusiformisLoveless [Fungus] 

Claviceps panicoidearum

Tanda & Y. Harada [Fungus] 

Heteroderadelvii Khan,Setty & Govindu  [Nematode]

Heterodera sacchariLuc & Merni[Nematode]

Peanut clumpfurovirus[Virus]

Peronosclerospora philippinensis

C. G. Shaw 

[Fungus]

Echinochloa spp. SON, 2003 Wilson, 2000Eleusine spp. SON, 2003 Brunt et al., 

2006

Miscanthus spp. CABI, 2007; 

JSCC, 2007; 

Tsukiboshi, 

2001

 

Panicum spp. Wilson, 

2000

 Wilson, 2000

Pennisetum spp. Wilson, 

2000

 Wilson, 

2000

Wilson, 2000

Setaria spp. Wilson, 

2000

Wilson, 2000

Tripsacum spp. Wilson, 2000 

2 The IPPC (2006) defines a quarantine pest as “a pest of potential economic importance to the area endangered thereby and no

present but not widely distributed and being officially controlled.” 

3 "Corn relatives”, for the purpose of this document, are Echinochloa spp. (barnyardgrass), Eleusine spp. (finger millet), Misca

Panicum spp. (millet), Pennisetum spp. (pearl millet), Setaria spp. (foxtail millet), and Tripsacum spp. (gamagrass). 

November 13, 2007 4 Draft 
Rev. Original November 16, 2007 5

Information available on quarantine pathogens previously reported (Reynolds, 1987) as 

associated with seeds of corn relatives (Table 3) was ambiguous or insufficient for this evaluation. 

Therefore, the pathogens in Table 3 were not analyzed further."

Table 3. Pathogens listed by Reynolds, 1987. 

Pest Scientific Name 

of Pathogen 

Present in 

U.S. 

Quarantine 

Pest 

Comments 

on the 

Pathway 

Distribution References 

Brachysporium 

senegalense 

NI1 NI NI NI NI 

Colletotrichum 

eleusinis 

NI NI NI NI NI 

Curvularia oryzae NI NI NI NI NI 

Drechslera 

pluriseptata 

NI NI NI NI Khetarpal, 

1984 

Pseudomonas 

eleusineae 

NI NI Bio-control 

agent 

NI Sitther, 

1996 

Pyricularia 

pennisetum 

NI NI NI NI NI 

Pyricularia setariae Yes 

(CABI, 

2007) 

No Bio-control 

agent 

(CABI, 2007) 

China, India, 

Japan, 

Malaysia, Sri 

Lanka, Africa 

(CABI, 2007)

Sorosporium cryptum NI NI NI NI NI 

Sorosporium 

kinshasaensis 

NI NI NI NI NI 

Sphacelotheca 

mcalpineae 

NI NI NI NI NI 

Tilletia ayresii No 

(Cline, 

2007) 

Yes NI Africa 

(Cline, 2007) 

NI

Tilletia eleusines NI NI NI NI NI

Tilletia setariae NI NI NI NI NI

Tolyposporium 

setariicolum 

NI NI NI NI NI

Ustilago confuse NI NI NI NI NI

Ustilago 

dactyloctaenii 

NI NI NI NI NI

Ustilago 

dactylocteniophila 

NI NI NI NI NI

Ustilago eleusinis NI NI NI Unconfirmed 

(CABI, 2007) 

NI

Ustilago idonea NI NI NI NI NI

=Ustilago panicigracile (Cline, 2007)

Sporisorium 

neglectum (Niessl) 

Vánky 1985 

NI NI NI Widespread 

(Cline, 2007) 

NI

Ustilago paradoxa NI NI NI NI NI

Ustilago pertusa NI NI NI NI NI 1

 Ambiguous or no host information available (CABI, 2007; Cline, 2007).
 Rev. Original November 16, 2007 

 

6

Summary

Peronosclerospora philippinensis, a fungal pathogen listed in the Agricultural Select 

Agent in the Agricultural Bioterrorism Protection Act of 2002 (CFR, 2005), is seedborne 

on Echinochloa spp., Panicum spp., Pennisetum spp., Setaria spp., and Tripsacum spp. 

Peronosclerospora philippinensis is a destructive disease of corn in tropical Asia that 

poses a severe threat to plant health and plant products in the United States. Furthermore, 

each of the corn relatives infected by P. philippinensis is also a seedborne pathway for 

other fungal, viral, or nematode quarantine pests (Table 2). The nematode Heterodera 

delvii and the peanut clump furovirus are seedborne on Eleusine spp. Heterodera delvii

may suppress corn yields (SON, 2003). Peanut clump furovirus causes severe yield loses 

in peanut crops, and in several legume and cereal crops (Wesley, 1996). The fungal 

pathogens Claviceps panicoidearum and Peronosclerospora sacchari follow the pathway 

on Miscanthus spp. Claviceps panicoidearum produces sclerotia in the plant head that 

are toxic to livestock (Tsukiboshi, 2001); it has a wide range that includes wheat, rye, 

timothy, and fescue. Peronosclerospora sacchari is severe on sugarcane and corn in 

Australia and Taiwan (PNKTO, 1986). 

None of the aforementioned pests is present in the United States, but they are likely to 

enter the country via seeds of corn relatives. All pests in Table 2 are present in one or 

more of the prohibited areas, including Africa, Australia, Brazil, Bulgaria, Japan and 

adjacent islands, Korea, New Zealand, Oceania, the People’s Republic of China, 

Southeast Asia, Taiwan, and the former Soviet Union (Brunt et al., 2006; CABI, 2007; 

Helms, 1987; SON, 2003; Tsukiboshi, 2001; Wilson, 2000). 

Recommendation 

The current APHIS administrative prohibitions for seeds of Echinochloa spp. 

(barnyardgrass), Eleusine spp. (finger millet), Miscanthus spp. (silver grass), Panicum 

spp. (millet), Pennisetum spp. (pearl millet), Setaria spp. (foxtail millet), and Tripsacum 

spp. (gamagrass) are justified and should be codified in the plants for planting 

regulations. 

A qualitative pest risk analysis using the methodology and rating criteria in Guidelines 

for Pathway-Initiated Pest Risk Assessment, Version 5.02 (USDA, 2000) is suggested for 

the following quarantine pests: Claviceps fusiformis (fungus), C. panicoidearum 

(fungus), Heterodera delvii (nematode), H. sacchari (nematode), peanut clump furovirus 

(virus), Peronosclerospora philippinensis (Chromista), and P. sacchari (Chromista), to 

potentially identify other seed hosts requiring regulation. 

Author 

L. G. Brown, Plant Pathologist/Senior Risk Analyst, USDA, APHIS, PPQ, CPHST 

Reviewers 

S. C. Redlin, Plant Pathologist/Senior Risk Analyst, USDA, APHIS, PPQ, CPHST 

R. A. Schall, Plant Pathologist/Risk Analyst, USDA, APHIS, PPQ, CPHST 
 Rev. Original November 16, 2007 

 

7

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