Idiobont
those parasitoid species that permanently paralyse their hosts during parasitism, causing the cessation of host growth and development
Kionobiont
parasitizes earlier host stages, host activity continues following the attack, and the association of the host and parasite is prolonged.
Phenology
Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors.
ecological/economic injury level
The smallest number of insects (amount of injury) that will cause yield losses equal to the insect management costs. Economic threshold. The pest density at which management action should be taken to prevent an increasing pest population from reaching the economic injury level.
epizootic
a disease event in an animal population akin to an epidemic in humans
antibiosis
adverse affects on pest life history, those that reduce herbivores’ performance.
an antagonistic association between two organisms (especially microorganisms), in which one is adversely affected.
antixenosis
adverse effects on pest behavior, avoidance traits, and those that affect herbivores’ behavior.
plant traits affecting herbivore behavior in ways that reduce the preference for, or acceptance of, a plant as a host by a herbivore.
quantitative defenses
- post-feeding affects on the herbivore
- effects dependence on consumption, deter herbivores, or slow the growth of herbivores rather than the toxicity.
- may comprise a significant proportion of the dry weight of living plant tissue
Qualitative defenses
- pre-feeding affects the herbivore, detering them from feeding on the host plant
- toxic in small doses
- often relatively cheap metabolically, a defense against unadapted herbivores
- present In low concentrations
- many plants employ both types of defense
Rapid induced resistance
- rapid, begins to act immediately after an attack, targeting the herbivore
- may be localized or systematic
- can be elicited by low levels of herbivory
Delayed induced resistance
- effect generations of insects subsequent to the one response for eliciting a response
- may have delayed-density effects, thus theoretically, can destabilize population dynamics and create cycles.
- generally need severe defoliation for elicitation
- driven by defoliation due to an imbalance of nitrogen and carbon
Escape-and-radiate coevolution
- a hypothesis proposed that the coevolution and evolutionary arms race between insects and plants resulted in the vast radiation and diversity of species.
- an evolutionary innovation by either partner in a coevolutionary interaction enables an adaptive radiation, or speciation due to the availability of ecological opportunity.
chemical defenses
A staggering array of plant secondary chemical defenses arise from photosynthesis and a few precursor pathways.
- Major classes of secondary compounds
~ terpenoids
~ N-containing
~ phenolics
to grow or defend dilemma
They must grow fast enough to compete, and yet maintain the physiological adaptations (de- fenses) necessary for survival in the presence of herbivores and pathogens
Enemy free space
- Some plant tissues may be inaccessible for some herbivore species because it may be too dangerous for them to feed on it.
- Jefferies and Lawton developed it in 1984
- herbivores may feed on suboptimal locations because they need to balance the quality of their food with the danger from natural predators
top-down or bottom-up?
an old debate in forest entomology on whether insect populations are regulated from the top-down or bottom-up. The answer is both, it depends on the species, the functional feeding guild, the population phase, and the geography
management for forest pests
- In most forests, insects do not require management. proactive strategies can reduce problems in the future
- Options
~ do nothing
~ pesticides
~ silviculture
~ biocontrol
~ semiochemicals
BTK biological insecticide
- The most used biological-derived control is the bacterium bacillus Thuringiunsis used as a spray or expressed transgenically in field crops
- has to be injected by the insect. crystallized spores dissolve in the insect’s midgut and release an endotoxin that perforates the cells of the midgut, killing the insect.
- fast-acting and low vertebrate toxicity
only effective during a short period in the insects development
nucleopolyhedrohedrosis virus NPV
a viral disease of caterpillars that occurs naturally in Australia. As a pesticide, NPV is highly specific, safe and environmentally friendly (does not harm humans, wildlife or other insects), making it ideally suited to include in an integrated pest management approach.
viruss/biocontrol-1
for tussock moths
Gypchek
for spongy moths
IPM - integrated pest management
- Includes ecosystem-based strategies focused on long-term reduction of pest damage through a combination of techniques
- can include biocontrol, habitat manipulation, change in cultural practice, plant resistance,
Sivilculture
the art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society
semiochemicals
chemical substances produced by organisms such as plants and animals, such substances elicit a physiological or behavioral response in individuals of the same or another species.
