Eating the leaves wont do much damage. Grow some chillis in summer and crush one and put it in a spray bottle of water and spray on the leaves of your plants.

I can help! I recently read here on MoMs that pepper sprinkled over the garden is meant to be great deterrent. I’ve yet to try it so can’t confirm. I’ve also read coffee grounds is good.

I also heard chilli works.

I haven’t tried it but, I have heard Garlic and Chili spray works?

Found a good article that describes common bugs and the signs to look for – here’s the summary!
Zucchini plants have a long growing season, which can leave them susceptible to damage from bugs that appear at different times of the year. Identifying the bugs helps you determine the best way to handle the pest problem. Some bugs can be removed by hand, while others require an insecticide. These include squash bugs, vine borers, cucumber beetles, stink bugs and aphids.
Vine borers are hard to spot. The first sign is often droopy stems and wilting leaves. If you look closely, you will see small holes in the stem and droppings beneath the plant that look like sawdust. Stink bugs, with shiny, leaf-shaped backs, often attack zucchini as it matures, leaving it misshapen or dimpled. Striped cucumber beetles usually attack early, while the plants are still seedlings. Look for stems that don’t seem to grow — because the tips are being eaten — or yellow and wilted leaves. They also eat holes through the leaves. Squash bugs eat the leaves and inject a toxin that causes leaves to dry up and wilt. They’re fairly easy to spot, with brown bodies growing to about 1/2 inch long with a pointed head. Aphids are harder to see, being extremely tiny, winged creatures. Look for nibbled edges or sticky spots on the leaves. Aphids sometimes gather on the underside of leaves, allowing you to see black spots if you tape a mirror to a hoe blade to peek under the leaves.
Pick off stink bugs and squash bugs by hand or use a general insecticide, such as carbaryl. Keeping the plants covered with a light gauze material can help keep the bugs away until the plants begin to blossom. If you suspect vine borers, cut a slit into the lower stem and scrape out any eggs or caterpillars. Insecticides containing carbaryl are often effective against vine borers. Pouring cold water mixed with 1 tablespoon of gentle dishwashing liquid can wash the aphids off the zucchini leaves and deter them from returning.
Planting certain plants near your garden can help keep pests away from your vegetables. Plant nasturtiums to attract the aphids away from your zucchini plants. Use alyssum, calendula or daisies to attract the Tachnid fly, which loves to eat squash bugs.

If you can find what’s eating the plant you’ll have a better chance of being able to prevent it. Some one suggested herbs – caterpillars demolished my herbs! Most plant shops have qualified people (even bunnings plan section) who are happy to have a chat with you – I suggest take a leaf (a damaged one) in a snap lock sealed bag so they can have a look and tell you what it is/how to treat it.

Plant marigolds with your veggie patch & they ward off the pests with their strong scent apparently.

Diatomaceous Earth is great as it only kills insects, you can order on line. It is safe and non toxic. sprinkle little in cupboards and behind or under furniture and your home will be free of unwanted critters as well.

Don’t know for in the garden, however if you have fleas tea tree oil diluted in a spray bottle spritzed everywhere seems to work really well. BUT be warned can be deadly to cats or so I have read. I moved into a rental that was riddled (covered to the knee in second) they sent pest control out it worked for rufly 6 months then they came back worse (at a guess I would say the eggs hatched with the weather change) tried so many thing then read about the tea tree. Apparently safe for dogs but really bad for cats although some sites I visited (Google can be your friend) people said that they washed their cats with it diluted right down with the blue dawn (not available in Australia although I have seen other colours in a discount pharmacy but they say the blue only is to be used). I mop my house with tea tree in the mop water and just keep the cat off the tiles until they are dry and if I notice a flea which has been only once I spray the carpet a few drops of Thursday Plantation tea tree to a spray bottle of water and I just mist it a spray approximately every metre (I have a large house with arthritic hands so I have to spay sparingly to avoid pain). I even find that if I have done the floors the cat comes in goes out and then comes back with less fleas later. Works for me

Peel your onions in a bowl of cold water. When finished use the water for pesticide on plants

Grown herbs around ur garden ,pots etc ,they detest mint & basil

I have been using the garlic spray with no luck

Try filling a spray bottle with water adding a minced clove or two of garlic and 2 tablespoons of dishwashing liquid and spraying it on.

I haven’t tried it yet but have heard place a few drops of lemon oil on the end of your broom & sweep around the corners of your ceiling & around doorways keeps spiders away