Hi, 

Unfortunately it is too difficult to see a close up on the leaves in the photo. The file format or size wont let us zoom in. 

From what we have found in our research, there is no indication that this is a seedless or sterile cultivar of barberry and they are invasive plants. Great for deer and rabbit resistance, since the thorns keep wildlife from eating them, however if they produce berries, the bird tend to eat them and spread seeds. There are many invasive forms in our native wooded area now which can lead to them outcompeting native plants and affect biodiversity of our native flora and fauna. 

Missouri Botanical Gardens does list this species as being somewhat susceptible to bacterial leaf spot and anthracnose. If you can send in a better photo, we may be able to decipher that. It could also be sun scorch because of the light colored leaves, even though this cultivar is supposedly more resistant to scorch than other golden-leaved barberries. 

There are some other gold leafed plants you may want to look into if that is the color you are going for. It will depend on the other site conditions and space, so just make sure the plant fits the area: 

Physocarpus opulofolius (Ninebark) 'Golden Nugget'

Sambucus racemosa (Elderberry) 'Lemony Lace'

Deutizia gracilis 'Chardonnay Pearls' (not native - but not invasive)

Thuja plicata ' Golden Spire' , 'Forever Goldy', 'Gold Feather' - there are a bunch of gold colored cultivars - if deer are a problem, these may not be the best plant choice. 

If you would like to attach more photos of the leaves, feel free to do so to this reply. 

Emily 

Hi Mike, 

This is looks like it could be an anthracnose disease or potentially a bacterial leaf spot disease, both which can cause premature leaf shedding. The best way to deal with it is to plant resistant cultivars, or as stated in the first response, plant different plants that are not invasive and don't have these common ailments. Since this is an invasive species that we discourage gardeners from growing, we have limited information about diagnoses and treatments for various conditions. 

However the 2 potential diseases mentioned, are mostly cosmetic and just cause the defoliation, and not overall harm to the plant. We wouldn't recommend a spray treatment since fungicides won't cure anything and probably aren't worth relying on for a yearly spray (or several). It would take multiple applications in the start of the growing season before the leaves emerge to treat for it and still potentially not have total control since it is an abiotic symptom caused primarily from weather conditions. Some leaf spot diseases can be treated with an all purpose fungicide like a copper foliar spray, but they won't be foolproof and the potential to harm other other organisms that come into contact with spray residues is at risk. 

For general sanitation practices that might help, make sure the fallen leaves in autumn are raked-up and disposed of and maybe try thinning the plant to improve air circulation through its branches and this could reduce the likelihood of infection. If it is leaf scorch from being in too much sun, you could attempt to move to a slightly shadier location, but it will probably cause the leaves to turn more of a lime green color and you would need to monitor for water conditions as the soil will be less likely to dry out and the plants could become prone to root rot if they stay too wet. 

Emily