Crop Biotechnology:Crop Biotechnology:a Weed Science Perspectivea Weed Science Perspective

Harold D. Coble

IPM Coordinator, USDA/OPMP

hcoble@ars.usda.gov

My PerspectiveMy Perspective

Reared on small diversified farm in 1940s-50sVery familiar with the drudgery of hand hoeingCollege degrees in agronomy & weed scienceWeed science extension & research for 30 yrsAlways been a farmer at heartA proponent of IPM – USDA IPM Coordinator

Photo credit USDA/NRCS

And, for many reasons,I believe in conservingour natural resources

Pest management is all about crop yield and qualitypreservation andease of harvest.

Photo credit USDA/NRCS

Pest Management StrategiesPest Management StrategiesThe PAMS ApproachThe PAMS Approach

Prevention– Cultural practices to keep pests out

Avoidance– Cultural practices to avoid or resist pest impact

Monitoring– What is present and how many

Suppression– Kill ‘em if you need to

Pest Suppression OptionsPest Suppression Options

Physical– Hand Weeding– Mechanical Cultivation– Other (mulches, , traps, etc.)

Biological– Insects, Bacteria, Fungi, Biochemicals

Chemical– Chemical Pesticides– Pheromones

Chemical Weed ControlChemical Weed Control

Historical non-selective chemicals (NaCl)Key to chemical use is selectivity

– Development of 2,4-D in 1940s– Research programs for selective herbicides– Rapid expansion of chemical use in 1960s &70s– ~100% major crop acreage treated today

Attaining SelectivityAttaining Selectivity

Massive chemical screening programsSelection in crop breeding programs

– Tracy soybean

Non-transgenic methods– Sethoxydim-tolerant corn (tissue culture)– STS soybean

Transgenic technologies (Biotech)

Growth of Biotech AcresGrowth of Biotech Acres% of Total U.S. Acres% of Total U.S. Acres

0

10

20

30

40

50

60

70

80

90

1996 1997 1998 1999 2000 2001 2002 2003

Soybean

Cotton

Field Corn

Biotech Crop UsesBiotech Crop Uses

0

10

20

30

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70

80

90

Corn (40) Cotton (73) Soybean (81)

Insects

Herbicide

Stacked

% of Acres

Western Corn Rootworm Adult

Photo credit USDA/ARS

Why the Rapid Adoption?Why the Rapid Adoption?Herbicide Tolerant CropsHerbicide Tolerant Crops

Lower cost of weed control, even with technology fees

Greatly simplified control proceduresHigher degree of weed controlFewer chemical applications = less trips Promotes more sustainable cultural practices

– Less tillage, less compaction, narrower rowsSocietal aspects (pride, landowner acceptance)

Higher degree of control at lower cost

Photo credit USDA/NRCS

And prevent disasters such as this

Photo credit USDA/NRCS

Why the Rapid Expansion?Why the Rapid Expansion?Insect Protection (PIPs)Insect Protection (PIPs)

High degree of control of target speciesSafety to beneficial speciesHuman and environmental safety

– Food/Feed safety– Applicator safety– Wildlife safety

Simplicity of control measures

PIPs aimed at themajor insect pestcomplexes

Photo credit USDA/ARS

Plant-incorporated protectants designed to avoid harm tobeneficials

Photo credit USDA/ARS

What’s the Downside?What’s the Downside?Herbicide Tolerant CropsHerbicide Tolerant Crops

Weed species shifts if integrated approach not used – Prevention and avoidance strategies– Continued field monitoring– Alternative chemical mode of action

Reduced availability of alternative MOAsTemptation to just plant and spray

Weed resistance isa fact of life

Photo Craig Chism, Univ. of TN

What’s the Downside?What’s the Downside?PIPsPIPs

Risk of resistance development/selection– Major concern of organic community

Increased cost if populations below EIL– Protection present whether needed or not

Have led to secondary pest resurgence– Stinkbugs in cotton

Tarnished Plant Bug

Photo credit USDA/ARS

Where do we go from here?

Tacos, Chicken feed,or Plastic??

Photo credit USDA/NRCS

Meat, Milk, or Pharmaceuticals???

Photo credit USDA/NRCS

We’ve only just begun…

Photo credit USDA/NRCS