Coconut milk and other coconut-derived ingredients feature heavily in the cuisines of central and southern Thailand. In contrast to these regions, coconut palms do not grow as well in northern and northeastern Thailand, where in wintertime the temperatures are lower and where there is a dry season that can last five to six months. In northern Thai cuisine, only a few dishes, most notably the noodle soup khao soi, use coconut milk. In the southern parts of northeastern Thailand, where the region borders Cambodia, one can again find dishes containing coconut. It is also here that the people eat non-glutinous rice, just as in central and southern Thailand, and not glutinous rice as they do in northern Thailand and in the rest of northeastern Thailand. Apples, pears, peaches, grapes, and strawberries, which do not traditionally grow in Thailand and in the past had to be imported, have become increasingly popular in the last few decades since they were introduced to Thai farmers by the Thai Royal Projects, starting in 1969, and the Doi Tung Project since 1988. These temperate fruit grow especially well in the cooler, northern Thai highlands, where they were initially introduced as a replacement for the cultivation of opium, together with other crops such as cabbages, tea, and arabica coffee. Food controversies Agricultural chemicals According to the Thai government's The Eleventh National Economic and Social Development Plan (2012–2016), Thailand is number one in the world in the application of chemicals in agriculture. The report stated that, "The use of chemicals in the agricultural and industrial sectors is growing while control mechanisms are ineffective making Thailand rank first in the world in the use of registered chemicals in agriculture." The Thai Pesticide Alert Network (ThaiPAN), a food safety advocacy group, annually tests Thai farm produce for contamination. In their June 2019 report, the group found that of 286 samples, 41% of produce was found to contain unsafe levels of chemicals. The group surveyed both wet markets and retail stores across the nation. Contaminants were found in 44% of samples from retail stores, and 39% of samples from wet markets. Vegetables with the highest levels of contamination were Chinese mustard greens, kale, hot basil, parsley, chilis, and cauliflower. Fruits with the highest contamination were tangerines, rose apples, guavas, and grapes. Contamination levels decreased from 2018, when 46% of samples were found to be contaminated, and 2016, when more than