Conn. Gen. Stat. § 23-61k
(a) Each arborist business shall maintain records for not less than five years from the date such record is made or amended, whichever is later. The record shall indicate:
(1) For each application of a pesticide made on behalf of the business, (A) the name and certification number of the commercial supervisor and the commercial operator, (B) the kind and amount of pesticide used and the amount of acreage treated, if applicable, (C) the date and place of application, (D) the pest treated for, and (E) the crop or site treated; (2) a list of the names and corresponding United States Environmental Protection Agency registration numbers of any pesticide applied by the business; (3) the names and applicator certification numbers of all certified commercial pesticide applicators, whether operator or supervisory, who are employees or agents of the arborist business, and a list of the types of applications that each applicator performs; and (4) for each site where arboriculture not involving the use of pesticides was performed:
(P.A. 13-203, S. 5.)