Do the costs of synthetic pesticides outweigh their benefits

? Provide food for growing population.

1950s, easy control of insect pests Environmental harm

Beluga whale carcass classified as hazardous waste More weeds today than in 1940

Human health effects Inuit women suffer from pollutants 2,500 miles away 20,000 people die/year from pesticide poisoning

Pesticides should be used only to prevent an economic loss and rarely should be used in a prophylactic manner.

Organic farming Grows food in harmony with nature (pro

article) No GMOs No CAFOs No antibiotics for weight gain Requires more energy Yields are lower Can it feed 7 billion +? No says Robert

Paarlberg

Alternatives to chemical pesticides are eco-friendly and sustainable

Crop rotations: alfalfa hay/corn/soybeans

Biological control: reduction of pests by natural enemies and typically involves an active human role

Conservation: Keep alive what is already there. Pesticides kill non-target

species Classical Biological Control

Uses natural enemies of pest. Parasites, predators, pathogens Augmentation

This third type of biological control involves the supplemental release of natural enemies.

Habitat manipulation: Many adult parasitoids and predators benefit from sources of nectar and the protection provided by refuges such as hedgerows, cover crops, and weedy borders.

Genetic engineering

Classic biological control : Predators

Predators are free-living species that consume a large number of prey during their lifetime.

Cottony cushion scale: sucks phloem sap from plants Vedalia ladybird beetle native to Australia feeds on

the scale 514 beetles released from November 1888 to March

1889. By 1890 all of the infestations of the cottony-cushion

scale had been eliminated. Bio success

Classic biological control : Weed feeders

Purple loosestrife – Galerucella beetles 1. determine the origin of the introduced pest 2. natural enemy a rigorous quarantine process reared, ideally in large numbers, and released.

Pathogens Pathogens are disease-causing organisms

including bacteria, fungi, and viruses. They kill or debilitate their host and are relatively specific to certain insect groups.

Formulations of the bacterium, Bacillus thuringiensis or Bt, for example, are widely used by gardeners and commercial growers.

Parasitoids: Attack pest host and kill it slowly, slower than a predator of the host. Life cycle of parasitoid is faster, more offspring Parasitoids are more susceptible to insecticides Parasitoid wasp For example, hyperparasitoids are parasitoids of

other parasitoids. In potatoes grown in Maine, 22 parasitoids of aphids were identified, yet these were attacked by 18 additional species of hyperparasitoids.

Genetic engineering Male insects exposed to radiation

become sterile Sterilized males, 10 – 100 above the

number of normal insects in the population are released

Females lay unfertilized eggs Worked well on screwworms

IPM the aim is to reduce pest populations to less than damaging numbers.

An ecologically based pest control strategy that relies heavily on natural mortality factors and seeks out control tactics that disrupt these

pest resistant or tolerant plants, and cultural: Physical: Mechanical: Biological: AND THEN chemical control

Economic or action threshold Economic threshold

The level of infestation or damage at which some action must be taken to prevent an economic loss.

Cost of pesticide Crop value - damage

Economic or action threshold

Economic threshold and sampling

The level of infestation or damage at which some action must be taken to prevent an economic loss is referred to as the "" Action thresholds are available for many vegetable crops. Ideally, these thresholds adjust for changes in market prices, stage of crop growth, cost of pesticides, etc., but in reality most are based on fixed infestation or damage levels.To estimate the severity of pest infestations, the crop or garden must be sampled. Sampling may entail examining plants and recording the number of pests or amount of damage observed, or traps may be used to capture the pest species to estimate pest abundance

Integrated Pest Management Control Tactics

Pest-resistant crops

Cultural Control

Physical and Mechanical Control

Chemical Control

Disease resistant crops Examples include varieties of wheat which

have tough stems that prevent development of the Hessian fly

cucurbits (squash, cucumbers, melons) that have lower concentrations of feeding stimulants (cucurbitacins) for cucumber beetles

Cultural crop rotation : Colorado beetles overwinter in or near

potato fields and they require potato or related plants for food when they emerge in the spring. With cool temperatures and no suitable food, the beetles will only crawl and be unable to fly. Planting potatoes well away from the previous year's crop prevents access to needed food and the beetles will starve.

trap crops : planted to attract and hold pest insects where they can be managed more efficiently and prevent or reduce their movement onto valuable crops.

Early planted potatoes can act as a trap crop for Colorado potato beetles emerging in the spring. Since the early potatoes are the only food source available, the beetles will congregate on these plants where they can more easily be controlled.

Physical and Mechanical Control

The use of physical barriers such as row covers or trenches prevents insects from reaching the crop. Plastic-lined trenches are effective in trapping large numbers of dispersing Colorado potato beetles in the spring and fall. Other methods include hand picking of pests, sticky boards or tapes for control of flying insects in greenhouses and various trapping techniques.

Chemical According to this method the major

classes of insecticides are the organophosphates, chlorinated hydrocarbons, and pyrethroids

Others in this classification system include the biologicals (or microbials), botanicals, oils, and fumigants.

Soil Conservation Crop residue: Leave some of last year’s

crop on the field, reduces erosion & increases soil fertility

No till or reduced tillage.