Table 3. Effect of pre-treatment with the synergist PBO in two UK cabbage stem flea beetle samples.

Sample	Treatment	N a	resistant beetles (%)	kdr genotype (%)
				SS	SR	RR
Hertfordshire	Untreated	9	89	22	33	45
	PBO	8	88	38	24	38
	100% λ-cyhalothrin	15	47	47	13	40
	PBO + 100% λ-cyhalothrin	11	27	27	27	46
Bedfordshire	Untreated	10	100	30	30	40
	PBO	8	100	25	13	62
	100% λ-cyhalothrin	15	40	27	27	46
	PBO + 100% λ-cyhalothrin	15	0	33	20	47

^aTotal number of beetles genotyped.