Hi Sue, thanks for the question.  

Probably the most important thing you can do is identify the problem.  Brown spots on leaves can be a symptom of pests, diseases, or cultural problems.  White pests could be aphids, or spider mites, whiteflies or other critters. Below are some resources that may help in identifying the problems.  Once the problem is identified a proper solution can be determined.  It is unclear about the "grubs" did you mean slugs?   A link on slugs is also added. On a final note, using home remedies for the garden can be risky and may not be good for your plants.  If you continue to have problems, get some pictures and we can help. Check out the following links:

Squash | Diseases and Pests, Description, Uses, Propagation (psu.edu)

Cucumber | Diseases and Pests, Description, Uses, Propagation (psu.edu)

Bean | Diseases and Pests, Description, Uses, Propagation (psu.edu)

Pepper, bell | Diseases and Pests, Description, Uses, Propagation (psu.edu)

Are Home Remedies a Good Solution? Penn State Extension Says No! (psu.edu)

Coming clean on soap in the garden | UMN Extension

https://s3.wp.wsu.edu/uploads/sites/403/2015/03/baking-soda.pdf

I hope this is helpful.