Pest management Flashcards
Intro
pest and specific
organism that interferes with human welfare activites - vaguely define- context specific ie bulbs S Africa versus Australia - swap and think other is pretty
sometimes due to numbers- quantity of locusts
can be bio control gone wrong ie cane toad
examples (5)
cotton bollworm Black rat black wattle malagasy locust cane toad
cotton bollworm
predates on corn
causes $1.1 billion damage
fungi develops in damages - GMO species goo and untouched
black rat
Ancapa island 3 inlets
80-90s decline of seabirds as rat introduced - eat bird eggs
4 years developng programme
helicopters for special rodenticides
10 yrs later eradication and birds thriving + new species - growth rate up to 25% in seabirds
black wattle
firewood, can extract tannin for leather common in S africa
But outcompetes other spp
uses more water than indigenous spp- water levels drop thus dry rivers-dam not effectoive-less irrigation-farmer cost
when cleared also problem as leopards came down as used to use as cover. affected wildstock as ate sheep.
malagasy locust
destroyed HALF of corn and rice crops in a matter of weeks. 100 swarms in madagascar, 5 billion locusts and 100,000 tonnes of vegatation affected.
climate change - wetter season allowed them to breed
usually arent pest.
Famine caused as well as famine t ocattle. $3 billion was spent on aid. was a v serious problem. Country was too poor to spend money on pesticides or fuel.
cane toad
introduced to remove beetles, ended up being pesst as ate everything- also eliminated larger predators as is toxic – bio control gone wrong
pesticides and natural example
not a new concept, chemical that repel or kill pests. Natural example is LANTANA- chemical relaease then kills pests around it. Chemicals have synthesised many.
rachel carson
Silent Spring “they should not be called pesticides but biocides” 1962- raised public awareness about toxicity and food contamination. Regards build-up of DDT killing birds and she grew up without hearing them sing.
hard and 2 examples
high toxicity, persistent (long term), build up in enviro, up food chain – removing predator can lead to prey pop explosion. Examples are DDT and Chlorinated hydrocarbons
soft
low toxicity, not persistent (short-term), easily degraded by enviro-break down in water/air – don’t harm people or enviro – soaps, washing up liquid, oils baking soda, plant extracts.
target specific examples
herbicides, nematicides, rodenticides, insecticides, algaecides, and bactericides
how do the ywork 5
1) CNS
2) Photosynthesis inhibitors
3) Smothering- oils
4) Dehydration
5) Inhibition of blood clotting
Sparks ethical debates wrt animal use.
how do they work heading
LD-50 – MENDELIAN LETHAL DOSE – figure out how much on average takes to kill the pest – action on 5 things
benefits (3)
1) Food – 55% before and after harvest of food is lost – would be even higher withouth pesticides – food prices would rise
2) Clothing – without control of cotton bollworm would have lestt cotton produced
3) Disease – Tse Tse fly (sleeping sickeness), Plasmodium (malaria), traitome (Chagas disease) rat fleas (bubonic plague) typhus (body lice and fleas) – many disease would be worse. Can save human lives. Prevent insect transmitte disease – vectors often cryptic
BENEFITS OF APPLICATION 6
1) Quick
2) Cheap
3) easy to apply
4) safe when handled correctly
5) long shelf life
6) if gen resistance can switch to other pesticides / stronger ones
disadvanatages 4/8
1) Non-specific /non target organisms- USDA – 2% from aerial spray reach pests only. 5% applied to crops reach target weeds.mobile through air (soft), hard (water)
2) Bioaccumulation – increase in chemical concentration in specific tissues /organs and scored in bodyfat
3) Persistence in environment – DDT has large lag time between application and degradation- unsure costs.
4) Food /water contamination – run off into our water supplies after sprayed
disadvantages last 4/8
5) Pesticide poisoning - short term to high levels= death, long term to small levels = CANCER and CNS WHO estimates . 3 million people poisoned each year – mostly developing countries – lack of regulations. Avoid poisoning – wash/scrub , organic or grow own veg, trim fat from meat and eat less or no meat.
6) Genetic resistance –wthin 5-10 yrs can be resistant- 17 insect pests are resistant to ALL major insecticide classes silver whitefly super pest causes farmers $200 million a year in crop losses (US)
7) Antibiotic resistance – many bacteria resistant. ½ antibiotics prescribed unnecessarily
8) New pests – can effect nat predator balance. Predators must be killed so natural pop rebound. DDt example- use of DDT caused outbreak of SCALE insects that weren’t there before.
Safer pesticide development:
BOTANICALS AND MICROBOTANICALS – asafer as nat products
regulation
Regulating use – tolerance levels- health authorities- max toxic residue legally allowed LEGISLATION AND LABELLING PRODUCTS
traditional alternative control 2
1) Physical: rotate between crops, selective breeding, grafting to bind strong roots and fruit bearing.
2) Ecofarmer: each crop planted exclusively as part of ecosystem- integrated approach
bio control 4
1) Predator/parasites – wasp for gypsy moth caterpillar- can become pest itself
2) Microbials – Bt toxin – soil bacteria toxin kills specific pests ie weeds
3) Diseases – use bacteria and virus- synthetic biology – alga from scratch-grows on eroding soils to stop erosion
4) Natural repellents – garlic, sulphur, pyrethins
other alternative control 5
1) Timing – so pest starves / certain season/day time mean less pest prone system T
2) Type of crop – diversity reduces losses T
3) Photdegradable plastics- plastics that degrade in sun – stop weeds
4) Traps using pheromones- to lure pests into trap
5) Vacuum pests – time consuming)
genetic 4
resistant
gene drive
sit
integrated
resistant
1) Resistant crops – transgenics to acieve pest resistant crop ie Tomato plant (used to take 1-20yr-natural breeding
SIT
3) SIT - Sterilization – male raised in lab,sterilised by gamma radiation or chemicals,released into enviro, mate unsuccessfully wilth wild ferile females. Pops die out – success in Zanzibar and Florida screwworm – need large numbers
- Steroid hormone 20E passed to mozzie during sex induces egg laying and makes her unreceptive to males therefore stops mating AGAIN. Now basing sterilising compound on this.
- Plutella diamond moth – double sex DSX gene was alternatively spliced to create lethal genetic system- also promise to broaden SIT control
steroid hormone
20E
integrated technique
houseflies causing diarrhoea- 2 formulas being developed- chemical and microbrial. Overcome resistance to pytheroids- will hit market in 6 months – good results in poultry farm trials. NBAIR but patent will be sold to pivate players once market has been developed
old fly resistant to
pytheroids-
