Stink bugs on tomato plants
Hi- garlic will not be effective. Neem oil is most effective if the spay directly contacts young stink bugs, soon after hatching from eggs (nymphs). Neem oil and other organic insecticides will be only nominally effective against the adults. Brown and Southern green stinkbugs are the two native species we most often see, although brown marmorated stink bug is still active in MD. Stink bugs are difficult pests when the populations are high. Commercial growers using chemical insecticides have a hard time managing stink bugs!
Handpick and destroy egg masses if you can locate them in the upper canopy on leaf undersides.
Stink bugs also feed on various weeds so keep weeds under control.
Pick fruit that are just barely turning and allow them to ripen indoors. This will prevent some feeding injury.
More stink bug information: