Hello, I'm Dr. Deb. I'll do my best to help you today.
I'm sorry for this concern for Allegro.
While I can understand why you might think her diarrhea issues are related to the bug spray which your husband used, unless she directly ingested some of the spray, her loose stool problem isn't likely to be related. But if it is, then improvement should be seen within one day.
I suspect she's a little sluggish today because she didn't get a good rest last night.
There are any number of possible reasons why a dog might acutely develop diarrhea such as dietary indiscretion, internal parasites, Inflammatory Bowel Disease, viral or bacterial infections...and these are just a few examples.
Since she's only been sick less than 24 hours, it's possible that you may be able to treat her symptomatically for day or so and she will get past this.
1. Feed a bland diet of 1 part boiled chicken
(or hamburg) to 4 parts 20-minute white rice. Feed only a small amount of one time, 3-4 times through the day. I would not feed any regular dog food.
2. If she is not currently taking any aspirin or nsaid products and is not vomiting, then you can give Regular Strength Pepto Bismol. The dose would be 1 ml per 10 lbs of body weight 2-3 times a day.
For example, if she weighs 10 lbs, then you would give her about 1/4th of a teaspoon at one dose.
Pepto bismol should not be given to vomiting dogs since it contains salicylates (the active ingredient in Aspirin) which can irritate the stomach
3. I'd also consider starting her on a good quality, canine probiotic such as Forti Flora or Resources Protegrity GI. These products can be extremely useful for gastrointestinal issues (and to help strengthen the immune system as well). They may be available at local pet/grain stores.
4. Continue to encourage her to drink; you might even offer her Pedialyte which can help replace electrolytes lost with the diarrhea.
Or low sodium chicken broth may be more palatable for her.
I hope this helps and that you see improvement soon. Deb