Pesticides
There are over 40,000 different pesticide products on the market, involving more than 900 different active ingredients. An active ingredient means, of course, that it kills the pest, and an inert ingredient means that it does not kill the pest. However, inert ingredients do not necessarily mean they are harmless to humans! Thus, we have an overwhelming task in understanding this wide range of pesticides.
To help sort through the issues, we divide the active ingredients by means of their chemical characteristics as shown below.
A. inorganic pesticides are made from inorganic chemicals:
1. Boric acid powder: especially used for controlling roaches
2. Sodium fluoride: also used for roaches
3. Paris Green: made from arsenic trioxide + copper acetate
4. Silica gel (SiO2): a dessicant, it kills the bugs by drying them out
B. botanicals: many plant have evolved their own pesticides,
and humans have mae effective use of
these "natural" pesticides
5. Pyrethrum from chrysanthemums, often used with
a synergist (i.e., combined with piperonyl butoxide)
synthetic forms are called pyrethroids
6. Rotenone roots of the Derris plant (a legume)
used as dusting powder for ticks on animals
synthetic forms are called rotenoids
7. Nicotine: usually nicotine sulfate
C. chlorinated
hydrocarbons: usually low toxicity, but high persistence in environment
8. DDT: dichloro diphenyl trichloroethane
9. others: mirex, endrin, dieldren, chlordane, BHC,
heptachlor, toxaphene
D. organophosphates: usually low persistence, but high toxicity
acetylcholinesterase inhibitor
10. Parathion,
Malathion (malathion is an exception,
being relatively low in toxicity)
11. DDVP (Dichlorvos)
Diazinon
E. carbamates: also an acetylcholinesterase inhibitor
12. Carbaryl (Sevin)
Aldicarb
A. anticoagulants: multiple doses kill by internal bleeding in the rodent
1. warfarin low toxicity in humans,
but newer rat strains have developed resistance
2. others: pival, fumarin, PMP, diphacinone
B. botanicals:
3. Red squill: (from the plant)
a natural emetic (causes vomiting)
this is deadly in rats, because they cannot vomit
and instead choke and die (nasty but effective)
4. others bay leaves, cucumber skins
C. quick kill: extremely toxic
5. 1080 (Sodium Fluoroacetate)
1081 (Sodium Fluoroacetamide)
only intended for registered pest controllers
6. others: Strychnine, Zinc phosphide, cyanide gas
ANTU (alpha naphtyl thiourea)
D. selective: toxic to Rattus genus
7. Norbromide: vasoconstrictor
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8. evidence of droppings, burrows
rodents: gnawing marks (wood, cement, wires, etc.)
urine (shiny streaks under blacklight)
greasy runways (especially Rattus norvegicus)
9. other first, kill fleas (ectoparasite)
rodent controls: cement or steel curtains around house
to prevent burrowing
traps (traditional, or adhesive)
A. Alternative Pests Controls:
1. quarantine
2. antifeedants/ irritants to surface feeding insects
repellants: no feeding = starvation (e.g., pyrethrum)
3. natural birds, spiders
predators: bacteria, viruses (e.g., Bacillus thuringiensis)
Gambusia affinis (eats mosquito larvae)
4. agricultural irrigation (e.g., minimize standing water)
practices: rotate crops (some crops are naturally resistant)
destroy crop residues (reduces food for pests)
5. natural
pesticides: (e.g., botanicals)
6. resistant
crop strains: (genetic engineering)
7. pheromones: sex attractants:
confuses males in locating females
only minute amounts needed (low toxicity)
complements the use of pesticide
8. juvenile internal chemicals that regulate growth
hormones: (e.g., eggs hatching to nymphs)
if we can synthesize juvenile hormones:
altered concentration = no development
low toxicity
difficult for pests to develop resistance
9. autocide: insect sterilization (usually U.V. radiation)
sterile males mate with fertile females
most effective when pest population is low
complements chemical methods (which are more
effective when pest population is high)
B. Laws:
10. FIFRA (1947): Federal Insecticide,Fungicide, and Rodenticide Act
registers pesticides, requires testing
The most toxic pesticides are labeled Danger.
11. FEPCA (1972): Federal Environmental Pesticides Control Act
allows EPA to regulate pesiticides
12. ToSCA (1977): Toxic Substances Control Act -- allows EPA to:
require information from chemical manufacturers,
test new chemicals for
environmental and health effects,
regulate chemicals not addressed by other laws.
Harmful chemicals at the earliest stages of production are defined and listed under TOSCA.
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For more information, try: pests and pesticides
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