Cultivators have been using methyl jasmonate to enhance cannabinoid and terpene profiles for some time now. Terpenes & Testing reported on methyl jasmonate in the cannabis space as far back as 2018. This is around the time when experts were predicting that the applications of methyl jasmonate being used for the cultivation of other plants could be transferred over to the cannabis industry.
It was also in 2018 that a U.S. Patent 10,874,102 was filed for a specific process of using methyl jasmonate to increase terpene and cannabinoid production. Included in their patent application was a section that stated results from experimentation concluded that methyl jasmonate “raised cannabinoid and terpene levels”. 
Fast forward to today, over three years later, and discussions about using methyl jasmonate to enhance terpene production are still going on. Although methods can vary between cultivators, there still isn’t much direct scientific study of methods when applied to cannabis. However, the same can’t be said for applications enhancing terpene production in other plants, like the Douglas-fir tree.
Research on changes in terpene chemistry in the roots of Douglas-fir trees after being treated with methyl jasmonate was published in Tree Physiology.  Researchers concluded “methyl jasmonate significantly increased the concentrations of several monoterpenoids”, including linalool, camphene, myrcene, pinene, and more. Similar results for increasing terpene production were also found in research regarding the application of methyl jasmonate to the Norway Spruce. 
In both studies, the application of the methyl jasmonate causes a defense mechanism in the plant. This then triggers the production of more resin glands, terpenes, and other biochemical compounds that are produced as part of a plant’s biological defense system. There is plenty of scientific evidence to confirm that methyl jasmonate does affect terpene production in a variety of plants, but we’re still lacking studies specific to cannabis.
1- Heldreth D. Use of ABA/methyl jasmonate/sugar to increase terpene and cannabinoid production in Cannabis sativa. United States Patent Office. 2018
2- Huber D, et al. Changes in anatomy and terpene chemistry in roots of Douglas-fir seedlings following treatment with methyl jasmonate. Tree Physiology. 2005. 25:1075-1083. https://academic.oup.com/treephys/article/25/8/1075/1653133 Times Cited: 62 Journal Impact Factor: 4.196
3- Zhao T, et al. The influence of Ceratocystis polonicainoculation and methyl jasmonate application on terpene chemistry of Norway spruce, Picea abies. Phytochemistry. 2010. 71;11-12:1332-1341. https://doi.org/10.1016/j.phytochem.2010.05.017 Times Cited: 50 Journal Impact Factor: 4.072