_____________________________________________________________________________________________________ *Corresponding author: E-mail: jorcarvalho23@gmail.com, jromario_carvalho@hotmail.com; Journal of Experimental Agriculture International 44(2): 49-54, 2022; Article no.JEAI.83810 ISSN: 2457-0591 (Past name: American Journal of Experimental Agriculture, Past ISSN: 2231-0606) Castor Bean Cake: A Promising Alternative for Sustainable Spider Mite Management Amanda Gonçalves Alves a , Anderson Mathias Holtz a , Thiago Rodrigues Dutra a , José Romário de Carvalho b* , Ronilda Lana Aguiar a , Vergilio Borghi Neto a , Ana Beatriz Mamedes Piffer a , Caio Henrique Binda de Assis a , Ariana Magnago a and Natália Daros Fienni a a Federal Institute of Education, Science and Technology of Espírito Santo, Colatina, ES, Brazil. b Secretary of Education of the State of Espírito Santo, Jerônimo Monteiro, ES, Brazil. Authors’ contributions This work was carried out in collaboration among all authors. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JEAI/2022/v44i230797 Open Peer Review History: This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc are available here: https://www.sdiarticle5.com/review-history/83810 Received 28 December 2021 Accepted 01 March 2022 Published 08 March 2022 ABSTRACT Tetranychus urticae is an important phytophagous and cosmopolitan pest, affecting several cultures worldwide, such as papaya, strawberry, cotton, beans and soybeans. Chemical pesticides for mite control pollute the environment, poison humans and select resistant mite populations. Ricinus communis cake is a by-product of biodiesel production, containing compounds, such as ricinin and some fatty acids, described as toxic to arthropods. The objective of this work was to evaluate the castor bean cake acaricide potential on the spider mite, T. urticae. Ricinus communis dried seeds were pressed for oil extraction. Subsequently, the cake obtained after the oil extraction was ground in a knife mill to produce a fine powder. After, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 grams of castor bean cake powder were mixed into 100 mL of Tween 80 aqueous solution 0.05 % v v -1 , stirred (30 minutes, at 25 °C) and left to rest (20 minutes) to decant the solid particles. Finally, the supernatant (castor cake extract) was separated from the solid part by simple filtration. For direct application, 6 mL of castor cake extract were sprayed onto 10 T. urticae females dispersed on a 4 cm diameter Canavalia ensiformis leaf. For indirect application, 10 T. urticae females were placed in discs leaf, previously immersed in castor bean extract. Ten replicates were used for each treatment, evaluating Original Research Article