IPM Evolution Continued

Reading Assignment

Norris et al. Chapter 2. Pests and Their Impacts. Pp. 15 - 45

Silent Spring in Context of its Time

In the 10 years before Silent Spring…• Many new innovations were introduced.

Pesticides were viewed as one of them.• Widespread attitude was that man could

control nature. Pesticides were a manifestation of that view.

• After the depression & war, people wanted to believe that the govt & corporations could be trusted.

Silent Spring Coincided with Other Events

• 1962 – John Glen’s first orbital flight.• 1962 – Thalidomide taken off market

(problem identified 11/61, public outrage throughout 1962).

• 1962 – Cuban Missile Crisis• 1961 – 1963 – MLK’s movement climaxes• 1961 – 1963 – US increased presence

from 900 to 16,000 in Viet Nam• 1963 – JFK assassinated

Silent Spring Aftermath

• 1963 – President’s Science Advisory Committee issues report calling for reducing pesticides’ effects.

• 1963 – Senate calls for creation of Environmental Protection Commission

• Early – mid ’60’s – Increased sensitivity in analytical equipment enables detection of ppb’s. Including other chemicals.

• 1965 – First pesticide food tolerances

As the Effects Spread …

• Public became increasingly negative toward chemical companies.

• 1970 – EPA established.

• 1972 – DDT banned (biomagnification)

• 1973 – IBP project started– Emphasized pest control as a system– Introduced pest modeling/decision tools– Only for insects

IPM Concept Solidifies in the 1970’s

• 1975 – First textbook, Metcalf & Luckman (former had been criticized in SS)

• 1978 – CIPM project replaces IBP– Included weeds & plant pathogens– Included economic analyses

• 1978 – KY statewide IPM program began

IPM Becomes Ingrained

• 1984 – IPM becomes an annual federal budget item

• Large-scale scouting programs rise, decline, and stabilize in the 1980’s

• 1993 – National IPM Initiative: 75 % of US cropland to have IPM by 2000

• 2000 – National effort to develop “Crop Profiles” and “IPM Strategic Plans”

Current Status

• IPM widely recognized as the proper approach to dealing with pests in production agriculture.

• Implementation is up to individual farmers so it varies considerably

• Concepts are well established but the technology continues to improve.

Significance of Pests in IPM

By Wednesday, Read Norris et al. Chapter 5, Comparative Biology of Pests

Impact Related to Direct & Indirect Effects

Comparison of Direct and Indirect Pests

Characteristic Direct IndirectCommodity Marketable Non-Marketable

Yield-Pest Relationship

Simple Complex

Pest Status Usually Key Pest Any

Pest GroupInsects & Pathogens

Any

Farmer Tolerance Low Higher

General Impact of Pests -- Injury

• Consumption of plant parts

• Chemical toxins, elicitors, and signals

• Physical damage

• Loss of harvest quality

• Cosmetic damage

• Vectoring of pathogens

• Direct contamination

General Impact of Pests – Non-injury

• Costs incurred to implement controls

• Environmental and social costs

• Regulatory costs (embargoes, quarantines, shipment costs, etc.)

Crop Injury in More Detail

• Crop Injury– Tissue Injury

• Leaves • Structural • Roots • Flowers and Fruiting/Reproductive Tissues• General Systemic Injury

– Competition• Water, Light, Nutrients

– Allelopathy

Tissue Injury to LeavesAbscission -- Leaf prematurely dropped by the plant, often while still green.

Tissue Injury to LeavesBleaching Leaf turns white or nearly so. Usually caused by using the wrong herbicide.

Tissue Injury to LeavesChlorosis Leaf tissue loses its chlorophyll and turns yellow. May occur in spots.

Chlorosis in soybeans. Individual leaves (left) and at the field level (right).

Tissue Injury to LeavesCrinkling Leaf takes on a crinkled texture. Usually associated with viruses or toxic effects of saliva from homopterous insects.

Crinkling may occur throughout the leaf (left) or may be confined to edges (right).

Tissue Injury to LeavesCupping and Curling Leaves cup up or down or they curl inward from the edges.

Downward cupping along main vein of each leaflet in soybeans caused by Bean Common Mosaic Potyvirus

Tissue Injury to LeavesEdge Feeding Leaves chewed and eaten from the edges. Feeding lesions can have smooth or jagged edges. Usually caused by insects w/chewing mouthparts.

Leaf edge feeding on rhododendron leaves by adult black vine root weevils.

Tissue Injury to LeavesHole Feeding Leaves have holes chewed through them. Caused by insects w/chewing mouthparts.

Yellow poplar weevil adult feeding on yellow poplar

Tissue Injury to LeavesMines Caused by small, immature beetles or flies that live in-between the upper and lower leaf surfaces. The shape of the mine, along with the plant species being attacked, is useful in identifying the pest species involved.

Frass-linear leaf mine on birch leaf. Mines come in many shapes.

Tissue Injury to LeavesMottling Leaf is not uniform in color but is, instead, a mottled mixture of different shades of green to yellow.

Soybean leaf mottling caused by the Bean Pod Mottle Virus.

Tissue Injury to LeavesNecrosis Areas of dead tissue which usually sloughs off over time.

Necrosis simply means dead tissue and may occur in any pattern. Necrosis may be in spots (top left), on leaf margins (above), or follow leaf veins (bottom left). Other patterns are possible as well.

Tissue Injury to LeavesRolling Leaf is rolled up like a cigar. Usually caused by caterpillars that use the rolled leaf as a pupation chamber.

Leaves may be rolled entirely (above) or only partially (left).

Tissue Injury to LeavesShothole Small holes in a straight line across the leaf. Usually caused by insects that bore through the developing leaf when the un-emerged leaf is still rolled up in the plant’s whorl.

Tissue Injury to LeavesSkeletonization Leaf tissue between the veins is removed but the veins remain intact leaving a skeleton-like appearance.

Lindin leaf skeletonized by Japanese beetle. Note that the distal leaf tissue is relatively normal looking indicating that the leaf veins are fully functional.

Tissue Injury to LeavesSpots Caused by fungal, bacterial, and viral diseases. Spots vary in size, shape and number and may be solid or only peripheral (e.g. ring spot, frog-eye spot).

Bacterial leaf spot on pepper

Fungal leaf spot on soybean

Viral ring spot on purple cone flower

Tissue Injury to LeavesStippling Large numbers of tiny pin-prick feeding lesions cause by mites or other minute herbivores with piercing-sucking mouthparts.

Leaf stippling by leaf hoppers (sucking insect). Non-uniform pattern. Stippling = dead cells surrounding feeding puncture.

Tissue Injury to LeavesWindowpaning One side of the leaf is scrapped off leaving the other side intact and translucent. This gives the feeding lesion a window-like appearance. Primarily caused by some young beetle and moth larvae.

Cereal leaf beetle windowpaning on wheat (left); European corn borer windowpaning on corn (right).