If you mean 'how to attract', then you can find tons of information searching on web. Attached file would be good source for you. https://www.ideals.illinois.edu/bitstream/handle/2142/29187/insectattractant1297wein.pdf?sequence=1
Mostly pheromone traps are best option as they are more target-specific. However, light traps and even yellow sticky traps also work well but depends on pest species and why you want to trap them.
There are many kinds of baits to attract insects depending on which kind of species do you want to work:
For nocturnal insects ultraviolet light traps are very useful. Likewise, mercury light and even led light lamps even attract many kinds of insects.
Synthetic pheromones are specific for attracting male Lepidoptera and coleoptera and are useful for studies of population dynamics or as pest control measures to lower populations in agricultural crops.
The use of baits based on eugenol and other terpenes serve to attract mainly euglossine bees and scolitid beetles.
Traps baited with alcohol and methanol are useful to attract diptera, coleoptera, hemipterans and other insect orders.
Hydrolyzed protein impregnated with molasses serves to attract fruit flies (Tephritidae and Drosophilidae)
Fermented fruits (banana, pineapple, mango) serve to attract butterflies, coleoptera and diptera.
Baited traps with rotten fish and excrement are very useful to attract coprophagous and necrophagous flies, beetles and butterflies.
As you can see there are many kinds of baits to attract different kinds of insects
If you want to attract a specific species of insects; Because pheromones are specialized, they performance better, but if you generally want to attract insects, light traps are more appropriate.
It depends on many things. :1. you can attract some insect by using sex or aggregation pheromone alone but for other species maybe pheromone + kairomone is attractant 2.Trap type and its color 3.The location and height of the trap installation 4. ....
It's is mainly depends on the behavior of insect species. For Eg: Nocturnal insects can be attracted towards light during night and Incase of pheromones you can attract many group of insects, because almost 50 to 60% of species specific lures started commercialising recent days.
Ultra violet light traps are used to attract a diverse number of insect orders. We used it to study or survey certain areas. But it depends on which insects you are studying.
It all depends on the type of insect you want to work with. Pheromones are very important in attracting insect with sex pheromones. There are many other ways, like i said it is the insect in question that determines the type of attractants.
However, only male insects are attracted to sex pheromones. If you want to attract both sexes; aggregating pheromones, plant volatile ( of major hosts) or light traps (depending on the behavior of the species you are working on) can be used.
Light attracts nocturnal insects and moths. Most pheromones on the market are female pheromones that attract male insects. Some aggregation pheromones are attracting male and female insects. Some plants are also attracting insects: Pennisetum purpureum attracts the moth Spodoptera, Melinis multiflora attracts insect and Solanum tuberusum attracts the Colorado beetles and many other plants attract pollinating insects by means of their colours and the smell of their nectar….
There are a few basic models that describe almost all insect traps. They can be a surface which is presented flat or is formed into baffles or cylinders; containers with holes on the sides, up or down; and funnels leading or placed on the container to hold the captured insects. However, different types of traps are used to insects moving through the air (i.e. flying or insects carried by the wind), terrestrial or itinerant insects, underground insects or insects. in general therefore the types always in relation to the inset itself