California Rice Pest Update Christopher A. Greer University of California Cooperative Extension Big Valley Ag Services Rice Grower Meeting Yuba City, CA March 9, 2008

California Rice Yields,

Issues Driving Yield Variability Weather-main cause Weather-main cause Delayed planting Temperature extremes Others Others Herbicide resistance New herbicide learning curve Shift in cultural systems Introduction/emergence of new pests Cost of production

California Rice Pests Past and Present Recent Pest History Recent Pest History Situation in 1996 Situation in 1996 Situation Today Situation Today Situation Tomorrow Situation Tomorrow New and emergent pests in last 10 years New and emergent pests in last 10 years Rice Blast Disease Rice Blast Disease Bakanae Disease Bakanae Disease Weedy Red Rice Weedy Red Rice False Smut Disease False Smut Disease

Rice Blast Disease Caused by Pyricularia grisea Caused by Pyricularia grisea First Identified in CA in 1996 First Identified in CA in 1996 Most important rice disease worldwide Most important rice disease worldwide Fungal spores dispersed by air Fungal spores dispersed by air Multiple cycle disease Multiple cycle disease Very dependent upon environmental conditions Very dependent upon environmental conditions Leaf wetness, high R.H., moderate temperatures Leaf wetness, high R.H., moderate temperatures May infect most aboveground plant parts May infect most aboveground plant parts

Summary of Host and Environment Almost all California rice cultivars are susceptible to rice blast Almost all California rice cultivars are susceptible to rice blast Cultivar M-201, M-205, and M-104 most severely affected Cultivar M-201, M-205, and M-104 most severely affected Breeders developed M-208 (resistant) Breeders developed M-208 (resistant) California environmental conditions are permissive but not optimal for rice blast California environmental conditions are permissive but not optimal for rice blast Relatively dry days Relatively dry days Little rainfall or cloud cover during season Little rainfall or cloud cover during season

Bakanae Disease First identified in CA in 1999 First identified in CA in 1999 Widespread and caused some significant yield losses in 2002 Widespread and caused some significant yield losses in 2002 Caused by Gibberella fujikuroi Caused by Gibberella fujikuroi Produces growth hormones gibberellin and fusaric acid Produces growth hormones gibberellin and fusaric acid Symptoms may be quite variable Symptoms may be quite variable

HealthyBakanae

Thoughts on Seed Handling Use certified seed and obtain the cleanest seed possible Use certified seed and obtain the cleanest seed possible Use an Ultra Clorox soak according to the label Use an Ultra Clorox soak according to the label Do not sit around too long after draining seed Do not sit around too long after draining seed Anything over 24hr may lead to multiplication of the pathogen and result in higher disease incidence even in treated seed Anything over 24hr may lead to multiplication of the pathogen and result in higher disease incidence even in treated seed Do not ship seed to the southern US! Do not ship seed to the southern US!

Weedy Red Rice Current Situation Identified in 2003 in Glenn Co. Identified in 2003 in Glenn Co. Has been identified in six fields (Colusa and Glenn Counties) Has been identified in six fields (Colusa and Glenn Counties) Working with growers to eliminate from infested fields Working with growers to eliminate from infested fields

Significance Yield loss Yield loss Quality issues Quality issues

Yield Issues Vigorous growth and tillering habit Vigorous growth and tillering habit Competition for space and resources Competition for space and resources Leads to reduced yields Leads to reduced yields No effective herbicides No effective herbicides

Quality Issue Red bran Red bran May lower grade of milled rice. Max. limit of 0.5% red rice and damaged kernels (singly or combined) for Grade U.S. No. 1 May lower grade of milled rice. Max. limit of 0.5% red rice and damaged kernels (singly or combined) for Grade U.S. No. 1 May increase cost to miller to remove red kernels May increase cost to miller to remove red kernels

Management Red Rice Workgroup Red Rice Workgroup UC, RRB, CRC, CCIA, RES, County Ag Commissioners UC, RRB, CRC, CCIA, RES, County Ag Commissioners Two phases Two phases Exclusion Exclusion Eradication Eradication Both dependent upon proper identification Both dependent upon proper identification

Plant Characteristics Taller and lighter in color Taller and lighter in color Leaves long and rough Leaves long and rough Has prominent ligules and auricles Has prominent ligules and auricles

Management Exclusion Exclusion Certified seed Minimize movement Eradication Eradication Field Scouting Seed dormancy Continuous flood Removal Rotation

Another One? False Smut False Smut Ustilaginoidea virens Ustilaginoidea virens Not a true smut Not a true smut Photo courtesy of IRRI

Parting Thoughts There are many other rice pests in the world that are currently not present in California (THEY ARE NOT WELCOME HERE!) There are many other rice pests in the world that are currently not present in California (THEY ARE NOT WELCOME HERE!) We need to be proactive and vigilant We need to be proactive and vigilant There are things that we each can contribute to rice pest management that will benefit the industry as a whole There are things that we each can contribute to rice pest management that will benefit the industry as a whole

2008 Needs Cooperators for small plot and large-scale fungicide trials for aggregate sheath spot (especially in Sutter and Yuba Counties) Cooperators for small plot and large-scale fungicide trials for aggregate sheath spot (especially in Sutter and Yuba Counties) Let me know if you have any nutrient deficiency/toxicity symptoms or physiological disorders (photos) Let me know if you have any nutrient deficiency/toxicity symptoms or physiological disorders (photos) Interest in on-farm alternative stand establishment system trial Interest in on-farm alternative stand establishment system trial Sign-up for Sutter/Yuba, Placer and Sacramento Counties Newsletter Sign-up for Sutter/Yuba, Placer and Sacramento Counties Newsletter Chris GreerPhone:

Questions?