What can I say, but what a challenge!
There are very few videos or tutorials on the use of manufactured dappled light. What I mean by this is the effect created using strobes, by placing a patterned object in front of the light to create the effect of light filtering through trees. Something that is nice to use with food photography, but as I tend to shoot mostly with strobe rather than natural light- lets just say it's an experiment in progress.
I saw one guy use acetate sheets with patterns printed on them, placed on the softbox - which you can buy, at a cost, but most likely not available here in Australia, and not cheap.
Another used laser cut mdf, which i think is custom made, but he places it close to the subject. Nice, but unless you have huge budgets, this is not that practical.
Of course there is great old diy cut out cardboard... you can make any pattern you want, or the laserlight option, which you place on your flash head and it projects patterns on your subject.
So, in my search I have experimented with the acetate option. I found cutout foam stickers from one of those recycle centres that sell craft supplies to schools and artists from industry waste. I even found acetate sheets there! I also tried black paper cutout option, cutting out leaf shapes in all shapes and sizes to create the effect of leaves on a tree.
I also tried these plastic dish racks from Daiso that had a flower pattern in them - which was essentially a flat piece of plastic with flower shaped holes in them - very cute, but obviously can only be used on small subject.
You could use screens of sorts- like from a garden centre, or die cut metal would be pretty, or peg board can be effective for certain styles of shots.
The main thing is experimenting with the distance of the 'screen' to the subject as opposed to the light source. I found that having the screen closer to the subject works better, and not diffusing the light too much.