Multiple Resistance of Acetolactate Synthase and Protoporphyrinogen Oxidase Inhibitors in Euphorbia heterophylla Biotypes

Abstract

Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX.

A field survey of crop management practices and distribution of ALS resistant Euphorbia heterophylla in two states in southern Brazil

“…We speculate the lack of mixture of herbicide from different mechanisms of action may have severe negative consequences for the selection of herbicide resistant biotypes. In fact, Trezzi et al (2004) documented the first case of multiple herbicide resistance in Brazil, in Paraná state, in the species Euphorbia heterophylla.…”

Inheritance of Resistance to Protoporphyrinogen Oxidase Inhibitor Herbicides in Wild Poinsettia

“…Plants were sown in pots containing 5 kg of soil. Throughout the experiment, the temperature in the greenhouse was maintained between 23 o C and 28 o C. The S and R biotypes were subjected to repeated self-fertilization and the selection of S and R plants was achieved through the application of ALS and PROTOX inhibiting herbicides (Trezzi et al, 2005).…”

“…rudis)) detected in the State of Kansas (USA), in 2001 (Heap, 2015). In 2004, a biotype of E. heterophylla with multiple resistance to PROTOX and ALS inhibiting herbicides was recorded in the State of Paraná (Brazil) (Trezzi et al, 2005 (Heap, 2015).…”

Resposta de biótipos de Euphorbia heterophylla a doses de glyphosate

“…Posteriormente, na década de 1990, foram encontrados biótipos de leiteira resistentes aos herbicidas inibidores da acetolactato sintase (ALS) (Grazziero et al, 1998b). Em 2004, identificaram-se populações de leiteira que desenvolveram resistência múl-tipla aos inibidores das enzimas ALS e da protopofirinogênio oxidase (PROTOX) (Trezzi et al, 2005). Recentemente, identificaram-se biótipos de leiteira com resistência múltipla ao glyphosate e aos inibidores da ALS no RS (Prado et al, 2006).…”