1815
The anticholinesterase ( antiChE ) organophosphorus ( OP ) and methylcarbamate ( MC ) insecticides have been used very effectively as contact and systemic plant protectants for seven decades .
 Chemical: organophosphorus; Chemical: methylcarbamate
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: organophosphorus; Chemical: methylcarbamate