The two most prominent molds that affect a citrus crop post-harvest are blue mold, and green mold. These two are caused by the single mold Penicillium digitatum. All citrus fruit growing regions have this mold and it is most certainly a serious threat to the crops.

Citrus fruit is made into an easy target for mold by way of being bruised or by being punctured while it is being packed or harvested. The mold is attracted to the juice that comes out of the damaged fruit on account of the fact that mold likes to grow in wet and humid environments.

And since most citrus is grown in temperate zones, there is no lack of these two qualities. If the fruit is in, say, a large shipping truck with a lot of other fruits, the mold could spread far into the shipment and cause a good portion of it to be riddled with mold infection.

And if the mold makes to the grocery store and the mold, by some miracle, goes unnoticed it could affect other items in the store. If the fruit is left on the tree and mold has spread to it then other fruit on the tree could be affected and the crop could be rendered useless.

The only actual difference between blue mold and green mold is color. There are virtually no differences in the effects the two molds have on fruit. The two molds also have very similar growing environments and necessities and have basically the same needs.

They must both grow in a temperature of around seventy five degrees Fahrenheit. Raising or lowering the temperature can slow the growth of these molds. As such, freezing the citrus fruits can stop the molds growth before any serious damage can be done. This is why most shipment trucks are equipped with a freezer, but many still do not have this feature.

Taking extra care of the citrus fruits is another way to prevent the spread of mold. Caring for the fruit helps to ensure that there is no puncturing or bruising. Fungicides are also a very popular, and a highly recommended, way of dealing with mold.