Overview of Insecticide Resistance - ACS Symposium Series (ACS

Chapter 2

Overview of Insecticide Resistance

George P. Georghiou

Downloaded by UNIV QUEENSLAND on April 14, 2013 | http://pubs.acs.org Publication Date: February 23, 1990 | doi: 10.1021/bk-1990-0421.ch002

Department of Entomology, University of California, Riverside, CA 92521 The incidence o f insecticide r e s i s t a n c e continues t o i n c r e a s e , having been recorded in at l e a s t 504 species o f i n s e c t s and mites, a 13% increase s i n c e 1984. In a number o f s p e c i e s , the presence o f m u l t i p l e r e s i s t a n c e has created a crisis situation due t o l a c k o f a l t e r n a t i v e , e f f e c t i v e and affordable insecticides. Most o f these cases concern pests in h i g h intensity cropping systems or vectors o f human disease t h a t are subjected t o organized c o n t r o l programs. Notable progress has been achieved in research on the b i o c h e m i s t r y , molecular genetics and dynamics o f resistance. These advances are d i s c u s s e d as they provide improved o p p o r t u n i t i e s for designing c o n t r o l s t r a t e g i e s aimed at forestalling or d e l a y i n g the e v o l u t i o n o f resistance. The doubtful d i s t i n c t i o n t h a t i n s e c t s have earned as the f i r s t pests t o have developed r e s i s t a n c e t o a p e s t i c i d e has continued t o keep them i n the s p o t l i g h t as r e s i s t a n c e has p r o g r e s s i v e l y expanded t o a l l types o f commercialized i n s e c t i c i d e s . The questions being asked today on how t o cope w i t h r e s i s t a n c e are no l e s s c h a l l e n g i n g than those asked when r e s i s t a n c e f i r s t appeared. It i s clear, however, t h a t the huge amount of research conducted d u r i n g the ensuing three quarters o f a century on the mechanisms, g e n e t i c s , and dynamics of r e s i s t a n c e i s an i n v a l u a b l e asset as we begin t o move from passive c o u n t e r a c t i o n o f r e s i s t a n c e t o preventive r e s i s t a n c e management. Resistance t o i n s e c t i c i d e s has been d i s c u s s e d r e c e n t l y i n two comprehensive symposia volumes (1,2) and i n s e v e r a l reviews (3-13) d e a l i n g w i t h the b i o c h e m i s t r y , dynamics, management, or economics o f the problem. My 0097-6156/90/0421-0018$07.00/0 © 1990 American Chemical Society

In Managing Resistance to Agrochemicals; Green, M., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1990.

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GEORGHIOU

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b r i e f overview cannot i n c l u d e the m u l t i t u d e o f t o p i c s t h a t q u a l i f y f o r d i s c u s s i o n . Many o f t h e s e w i l l be c o v e r e d i n o t h e r p a p e r s o f t h i s symposium. I s h a l l l i m i t m y s e l f t o d e v e l o p m e n t s t h a t I f e e l a r e o f s p e c i a l s i g n i f i c a n c e a s we contemplate f u t u r e d i r e c t i o n s . I s h a l l be c o v e r i n g A s t a t u s r e p o r t on t h e i n c i d e n c e o f r e s i s t a n c e w i t h emphasis on " c r i t i c a l " c a s e s ; Recent developments i n r e s i s t a n c e t o p y r e t h r o i d s ; The p r o s p e c t s f o r r e s i s t a n c e t o b i o p e s t i c i d e s ; P r o g r e s s i n r e s e a r c h on r e s i s t a n c e mechanisms w i t h emphasis on gene a m p l i f i c a t i o n ; a n d Diagnostic tests for resistance monitoring.


Status of

Resistance

In v i e w o f t h e e v o l u t i o n a r y n a t u r e o f r e s i s t a n c e , a d d i t i o n a l c a s e s a r e bound t o a r i s e a s new i n s e c t i c i d e s a r e b e i n g i n t r o d u c e d and s e l e c t i o n p r e s s u r e r e m a i n s h i g h . F i g u r e 1, b a s e d on a d a t a bank t h a t we a r e m a i n t a i n i n g f o r t h e Food and A g r i c u l t u r e O r g a n i z a t i o n o f t h e U n i t e d N a t i o n s (FAO), i n d i c a t e s t h e p r o g r e s s i v e i n c r e a s e i n t h e number o f s p e c i e s o f i n s e c t s and m i t e s w o r l d - w i d e , t h a t have d e v e l o p e d r e s i s t a n c e t o one o r more i n s e c t i c i d e s . The t o t a l o f 504 s p e c i e s i s p r o b a b l y an u n d e r s t a t e m e n t o f t h e p r o b l e m s i n c e many c a s e s o f p e s t c o n t r o l f a i l u r e undoubtedly remain u n i n v e s t i g a t e d or unreported. When t h e v a r i o u s c a s e s o f r e s i s t a n c e a r e g r o u p e d a c c o r d i n g t o t h e decade o f f i r s t o c c u r r e n c e , i t i s e v i d e n t t h a t t h e number o f new r e s i s t a n t s p e c i e s r e c o r d e d i n t h e p r e s e n t decade i s s m a l l e r t h a n t h o s e r e c o r d e d i n t h e p r e v i o u s decade, i . e . 90 v s . 190 s p e c i e s (Table I ) . T h i s i s b e c a u s e many o f t h e r e c e n t r e p o r t s c o n c e r n e x p a n s i o n o f t h e r e s i s t a n c e s p e c t r u m i n s p e c i e s w h i c h have p r e v i o u s l y been r e p o r t e d a s r e s i s t a n t t o o t h e r compounds. I t w o u l d t h u s a p p e a r t h a t most o f t h e e c o n o m i c a l l y i m p o r t a n t s p e c i e s have b y now d e v e l o p e d r e s i s t a n c e t o a t l e a s t one insecticide. Table

I.

Period 1908 1909-1918 1919-1928 1929-1938 1939-1948 1949-1957 1958-1967 1968-1978 1979-1988

C h r o n o l o g i c a l I n c r e a s e i n Number o f I n s e c t s and M i t e s w i t h Documented C a s e s o f Resistance to P e s t i c i d e s New

Number o f i n Decade 1 2 2 2 7 62 148 190 90

Soecies Total 1 3 5 7 14 76 224 414 504


MANAGING


600

RESISTANCE

TO

AGROCHEMICALS

r

F i g u r e 1. C h r o n o l o g i c a l i n c r e a s e i n t h e number o f i n s e c t and m i t e s p e c i e s r e s i s t a n t t o a t l e a s t one t y p e o f i n s e c t i c i d e ( t o t a l ) , and s p e c i e s r e s i s t a n t t o e a c h of the 5 p r i n c i p a l classes of i n s e c t i c i d e s .


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C y c l o d i e n e i n s e c t i c i d e r e s i s t a n c e i s f o u n d i n more s p e c i e s t h a n any o t h e r t y p e o f r e s i s t a n c e : 291 s p e c i e s a r e a b l e t o r e s i s t t h i s c l a s s o f i n s e c t i c i d e , compared t o s m a l l e r numbers f o r DDT, OPs, c a r b a m a t e s o r p y r e t h r o i d s ( T a b l e I I ) . The p r e p o n d e r a n c e o f r e s i s t a n c e t o t h e c y c l o d i e n e s i s a l m o s t c e r t a i n l y due t o t h e l o n g p e r s i s t e n c e o f these chemicals i n t h e environment.


T a b l e I I . The O c c u r r e n c e o f R e s i s t a n c e i n I n s e c t s and M i t e s A c c o r d i n g t o P e s t i c i d e C h e m i c a l Group C h e m i c a l Group Cyclodiene DDT Organophosphate Carbamate Pyrethroid Fumigant Other

Number o f S p e c i e s 291 263 260 85 48 12 4Q

P e r c e n t Of T o t a l 57.7 52.2 51.6 16.9 9.5 2.4 7^2

The m a j o r i t y o f r e s i s t a n t s p e c i e s (56.1%) a r e o f a g r i c u l t u r a l importance, but a s u b s t a n t i a l p r o p o r t i o n (39.3%) r e p r e s e n t s i n s e c t s o f m e d i c a l i m p o r t a n c e , e s p e c i a l l y m o s q u i t o e s and f l i e s . O n l y 4.6% a r e b e n e f i c i a l s p e c i e s ( p r e d a t o r s , p a r a s i t e s , o r p o l l i n a t o r s ) (Table III). F o r a d e t a i l e d index o f cases o f r e s i s t a n c e see G e o r g h i o u , G. P.; Lagunes, A., The O c c u r r e n c e o f R e s i s t a n c e £o_ P e s t i c i d e s i n A r t h r o p o d s 2ndfid.,F.A.O. : Rome, i n p r e s s . r

Table I I I . R e s i s t a n t I n s e c t and M i t e Species A c c o r d i n g t o Economic I m p o r t a n c e Economic I m p o r t a n c e Agricultural Medical/Veterinary Beneficial

Number o f S p e c i e s 283 198 23

Percent 56.1 39.3 4.6

C r i t i c a l Cases o f R e s i s t a n c e T h e r e a r e a number o f e s p e c i a l l y c r i t i c a l c a s e s o f r e s i s t a n c e i n which n e a r l y a l l o f t h e a f f o r d a b l e , p r e v i o u s l y e f f e c t i v e i n s e c t i c i d e s have been d e p l e t e d . Most o f t h e s e c a s e s c o n c e r n h i g h i n t e n s i t y c r o p p i n g systems, o r v e c t o r s o f d i s e a s e t h a t a r e s u b j e c t e d t o o r g a n i z e d c o n t r o l programs. A p a r t i a l l i s t o f such species follows: Diamondback moth Whitefly Green p e a c h a p h i d Leafminer Budworms

(Plutella xylostella) (Bemisia tabaci) (Myzus persicae) (Liriomyza trifolii) (Heliothis virescens) (H. armigera)


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MANAGING RESISTANCE TO


Colorado potato beetle Twospotted s p i d e r mite European r e d m i t e M a l a r i a mosquitoes Housefly German c o c k r o a c h Blackfly

AGROCHEMICALS

(Leptinotarsa decemlineata) (Tetranychus urticae) (Panonychus ulmi) (Anopheles spp.) (Musca domestical (Blattella germanica) (Simulium damnosum s.l.)

piamondfrack MQth, A m a j o r p e s t o f c r u c i f e r o u s c r o p s , t h e diamondback moth has d e m o n s t r a t e d one o f t h e h i g h e s t p r o p e n s i t i e s f o r development o f r e s i s t a n c e , e s p e c i a l l y i n s o u t h e a s t A s i a , and t h e F a r E a s t ( 1 3 - 1 5 ) . I n T h a i l a n d , where n e a r l y e v e r y a v a i l a b l e i n s e c t i c i d e has been u s e d and eventually f a i l e d , t h i s insect i s highly resistant to a v a r i e t y o f o r g a n o p h o s p h a t e s (OP), p y r e t h r o i d s , and c h i t i n i n h i b i t o r s , but c o n t i n u e s t o be s u s c e p t i b l e t o B a c i l l u s t h u r i n g i e n s i s (BT) and t o A v e r m e c t i n (JL£) . C a s e s o f r e s i s t a n c e i n t h i s s p e c i e s have a l s o been n o t e d r e c e n t l y i n t h e U.S. and C e n t r a l A m e r i c a , i n v o l v i n g OP, p y r e t h r o i d and carbamate i n s e c t i c i d e s ( S h e l t o n , A. M., N. Y. S t a t e A g r . Exp. S t a t i o n , Geneva, p e r s o n a l c o m m u n i c a t i o n , 1 9 8 8 ) . S e v e r a l mechanisms o f r e s i s t a n c e have been i d e n t i f i e d i n t h i s species, including carboxylesterase, general esterases, glutathione-S-transferase, i n s e n s i t i v e a c e t y l c h o l i n e s t e r a s e (AChE) (14-17) and k d r ( p y r e t h r o i d target s i t e insensitivity) (2A). Whitefly. P e s t s of h i g h v a l u e crops i n greenhouses or i n the f i e l d , are o f t e n s u b j e c t e d t o s t r o n g s e l e c t i o n p r e s s u r e by a v a r i e t y o f i n s e c t i c i d e s , r e s u l t i n g i n h i g h l e v e l s of broad spectrum r e s i s t a n c e . The w h i t e f l y , Bemisia tabaci, i s a c l a s s i c example o f s u c h r e s i s t a n c e , w h i c h a t t i m e s i s accompanied by m a s s i v e p o p u l a t i o n explosions. As d e s c r i b e d f o r t h e Sudan by D i t t r i c h e t a l . , t h i s s p e c i e s became a p r i m a r y p e s t o f c o t t o n i n t h e l a t e 1970 s, superseding the bollworm H e l i o t h i s armigera. Subsequent a p p l i c a t i o n s o f DDT/dimethoate t o c o n t r o l w h i t e f l y , b o l l w o r m and j a s s i d s , r e s u l t e d i n f a i l u r e o f c o n t r o l by d i m e t h o a t e , monocrotophos and o t h e r OPs by 1980/81 and a "tremendous f l a r e - u p " o f w h i t e f l y populations. More r e c e n t s t u d i e s have shown h i g h e r r e s i s t a n c e t o s e v e r a l OPs, c e r t a i n p y r e t h r o i d s , as w e l l as t o e n d o s u l f a n and methamidophos ( D i t t r i c h , V., C i b a - G e i g y L t d . , B a s e l , u n p u b l i s h e d data, 1988). S i m i l a r p a t t e r n s a r e e v i d e n t i n T u r k e y and e s p e c i a l l y i n G u a t e m a l a , where e x t r e m e l y h i g h l e v e l s o f r e s i s t a n c e (300x - 2000x) t o w a r d pyrethroids (deltamethrin, cypermethrin, fenpropathrin, b i p h e n t h r i n , c y h a l o t h r i n ) have been o b s e r v e d ( D i t t r i c h , V., u n p u b l i s h e d d a t a , 1988). f

Aphids. Resistance i n various species of aphids, e s p e c i a l l y those t r a n s m i t t i n g plant v i r u s diseases, r e m a i n s a s e r i o u s p r o b l e m . There a r e more c a s e s o f



2.

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Overview ofInsecticide Resistance

23

r e s i s t a n c e r e p o r t e d i n t h e g r e e n p e a c h a p h i d , Myzus persicae, t h a n i n any o t h e r s p e c i e s o f a g r i c u l t u r a l i m p o r t a n c e . Such r e s i s t a n c e has been r e p o r t e d f r o m 31 c o u n t r i e s i n v o l v i n g a t o t a l o f a t l e a s t 69 d i f f e r e n t i n s e c t i c i d e s , r e p r e s e n t i n g o r g a n o c h l o r i n e s , OPs, c a r b a m a t e s , and p y r e t h r o i d s ( G e o r g h i o u , G. P.; Lagunes, A., F.A.O.: Rome, i n p r e s s ) . R e s i s t a n c e i n t h i s s p e c i e s has been t h e s u b j e c t o f l o n g - s t a n d i n g , p r o d u c t i v e i n v e s t i g a t i o n s a t Rothamsted, U.K. R e s i s t a n c e i s due t o a c a r b o x y l e s t e r a s e (E4) w h i c h c o n f e r s b r o a d s p e c t r u m r e s i s t a n c e i n v o l v i n g n o t o n l y OPs b u t a l s o c a r b a m a t e s and c e r t a i n p y r e t h r o i d s (12.) . Three c l a s s e s o f r e s i s t a n t a p h i d s have been i d e n t i f i e d ( R i , R2, R3) b a s e d on t h e i n t e n s i t y o f t o t a l e s t e r a s e a c t i v i t y . E a r l i e r s u r v e y s had shown a p h i d s w i t h a moderate (Ri) l e v e l o f r e s i s t a n c e t o be w i d e s p r e a d i n t h e U.K. (2£i), but t h o s e w i t h h i g h e r r e s i s t a n c e (R2) t o be l o c a l i z e d i n n o r t h e r n E n g l a n d , S c o t l a n d , and l e s s commonly i n E a s t A n g l i a , w h i l e t h o s e w i t h t h e h i g h e s t l e v e l (R3) were a s s o c i a t e d w i t h g r e e n h o u s e c r o p s (20-24). More r e c e n t s u r v e y s , b a s e d on immunoassay o f E4 (25.) , r a t h e r t h a n t o t a l e s t e r a s e a c t i v i t y , i n d i c a t e an i n c r e a s e d frequency o f v e r y r e s i s t a n t R2 and R3 a p h i d s i n u n t r e a t e d f i e l d s i n s o u t h e r n and e a s t e r n E n g l a n d ( 2 £ ) . F i e l d t r e a t m e n t s a l s o r e v e a l e d t h a t a l l t h r e e m a j o r c l a s s e s o f a p h i c i d e s (OP, carbamate and p y r e t h r o i d ) s e l e c t f o r h i g h l y r e s i s t a n t i n d i v i d u a l s , e l i m i n a t i n g those w i t h s u s c e p t i b l e l e v e l s o f e s t e r a s e a c t i v i t y (21, 23.) . Leafminers. A r e l a t i v e l y recent case o f r e s i s t a n c e w i t h s e r i o u s i m p l i c a t i o n s f o r t h e f l o r i c u l t u r a l and v e g e t a b l e crops i n d u s t r i e s concerns the leafminer, Liriomyza trifolii. Over t h e p a s t t e n y e a r s t h e r e has been a d r a m a t i c r i s e i n t h e i m p o r t a n c e o f Liriomyza species as m a j o r p e s t s o f numerous o r n a m e n t a l and a g r i c u l t u r a l c r o p s (22.) and a w o r l d - w i d e e x t e n s i o n o f t h e g e o g r a p h i c d i s t r i b u t i o n o f some o f t h e s e i n s e c t s , m a i n l y t h r o u g h infested plant material. L. t r i f o l i i i s b e l i e v e d t o have been i n t r o d u c e d i n t o C a l i f o r n i a from F l o r i d a d u r i n g t h e l a t e 1970s on chrysanthemum c u t t i n g s and c e l e r y t r a n s p l a n t s . I t i s now r e c o g n i z e d a s t h e p r i m a r y p e s t o f chrysanthemum and a m a j o r p e s t o f c e l e r y and tomato QH) . D u r i n g t h e p a s t 10 y e a r s , t h e a v e r a g e e f f e c t i v e f i e l d l i f e o f an i n s e c t i c i d e u s e d a g a i n s t t h i s s p e c i e s i n F l o r i d a has been l e s s t h a n t h r e e y e a r s (21.) . I n t h e c o n f i n e d e n v i r o n m e n t o f g r e e n h o u s e s , i n w h i c h chrysanthemum c r o p s a r e p r i m a r i l y grown i n C a l i f o r n i a , t h e s p e c i e s has d e v e l o p e d r e s i s t a n c e t o p y r e t h r o i d s w i t h i n two y e a r s Q2.) . T h i s i s p e r h a p s not s u r p r i s i n g i n view of the extremely high frequency o f i n s e c t i c i d e a p p l i c a t i o n s made t o e n s u r e t h a t o r n a m e n t a l p l a n t s and c u t f l o w e r s a r e f r e e o f i n s e c t b l e m i s h e s , a s demanded b y t h e m a r k e t . I n a some s o u t h e r n C a l i f o r n i a greenhouse o p e r a t i o n s , i n s e c t i c i d e s are a p p l i e d w i t h a


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MANAGING

RESISTANCE

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AGROCHEMICALS


f r e q u e n c y o f one o r two p e r week t h r o u g h o u t t h e y e a r (2X). This case c l e a r l y i l l u s t r a t e s t h e h i g h r e s i s t a n c e p o t e n t i a l o f p e s t s i n g r e e n h o u s e e n v i r o n m e n t s , a s w e l l as the r i s k s f o r the spread o f r e s i s t a n c e w i t h the d i s t r i b u t i o n of infested plant material. Mosquitoes. I n s e c t i c i d e r e s i s t a n c e i n mosquitoes c o n t i n u e s t o be o f c o n c e r n , e s p e c i a l l y as i t i n v o l v e s d i s e a s e v e c t o r s p e c i e s o f Anopheles, Aedes and Culex. R e s i s t a n c e c o n t i n u e s t o impede t h e e f f e c t i v e n e s s o f w e l l e s t a b l i s h e d m a l a r i a c o n t r o l p r o g r a m s , s u c h as t h o s e o f P a k i s t a n , I n d i a , M e x i c o , and C e n t r a l A m e r i c a , and t h e i n i t i a t i o n o f l a r g e s c a l e c o n t r o l programs i n p o o r e r c o u n t r i e s , as i n A f r i c a . A c c o r d i n g t o d a t a o f t h e W o r l d H e a l t h O r g a n i z a t i o n , i n s e c t i c i d e r e s i s t a n c e i n Anopheles i s f o u n d i n 50 s p e c i e s , 14 o f w h i c h show m u l t i p l e r e s i s t a n c e t o 3 o r 4 c h e m i c a l g r o u p s . A t l e a s t 11 o f t h e 50 r e s i s t a n t s p e c i e s a r e i m p o r t a n t v e c t o r s o f m a l a r i a (33). The q u a n t i t i e s and s u c c e s s i o n o f i n s e c t i c i d e s u s e d i n t h e m a l a r i a c o n t r o l program o f P a k i s t a n , t h e chronology of f i r s t evidence o f r e s i s t a n c e i n the vector Anopheles Stephens! t o e a c h o f t h e i n s e c t i c i d e s employed, and t h e changes i n t h e i n c i d e n c e o f m a l a r i a a r e i l l u s t r a t e d i n F i g u r e 2. There i s s t r o n g e v i d e n c e f r o m a number o f a r e a s , e s p e c i a l l y i n C e n t r a l A m e r i c a , T u r k e y , t h e Sudan, I n d i a and e l s e w h e r e , t h a t heavy u s e o f i n s e c t i c i d e s on c e r t a i n c r o p s , s u c h as c o t t o n , a g g r a v a t e s t h e m o s q u i t o r e s i s t a n c e p r o b l e m by i m p o s i n g a d d i t i o n a l s e l e c t i o n p r e s s u r e on m o s q u i t o e s t h a t b r e e d i n t h e same e n v i r o n m e n t (34-36). Colorado Potato Beetle. Resistance t o i n s e c t i c i d e s i nthe C o l o r a d o p o t a t o b e e t l e , Leptinotarsa decemlineata, i nthe i n t e n s i v e p o t a t o g r o w i n g r e g i o n o f Long I s l a n d , N.Y., has a t t r a c t e d c o n s i d e r a b l e a t t e n t i o n b e c a u s e o f i t s economic i m p o r t a n c e , b r o a d s p e c t r u m , and r a p i d i t y w i t h w h i c h i t has e v o l v e d (1, 21)• F o l l o w i n g t h e development o f r e s i s t a n c e t o a l d i c a r b Q ) and t h e b a n n i n g o f t h i s i n s e c t i c i d e due t o the appearance o f r e s i d u e s i n underground water, growers resorted t o repeated a p p l i c a t i o n s of fenvalerate i n combination w i t h t h e s y n e r g i s t p i p e r o n y l butoxide (p.b.), t h e b o t a n i c a l i n s e c t i c i d e r o t e n o n e + p.b., and c o m b i n a t i o n s o f oxamyl and e n d o s u l f a n . The c o s t o f i n s e c t i c i d e s a l o n e was e s t i m a t e d a t $300 t o $700/ha (22.) . R e s i s t a n c e has r e c e n t l y l e d t o t h e r e p l a c e m e n t o f t h e s e i n s e c t i c i d e s by t h e b i o p e s t i c i d e BT s u b s p . tenebrionis and t h e i n o r g a n i c i n s e c t i c i d e c r y o l i t e (aluminum t r i s o d i u m fluoride). Rotenone and c r y o l i t e a r e pre-DDT i n s e c t i c i d e s t h a t were abandoned f o l l o w i n g t h e i n t r o d u c t i o n o f t h e more e f f e c t i v e , s y n t h e t i c o r g a n i c i n s e c t i c i d e s . N e i t h e r BT n o r c r y o l i t e are e s p e c i a l l y e f f e c t i v e against l a t e r - i n s t a r larvae or adults of t h i s species.



I960

1965

1970

1975

1980

1985

-18OOO

F i g u r e 2. Types a n d q u a n t i t i e s o f i n s e c t i c i d e s a p p l i e d annually f o rmalaria vector control i n Pakistan during 1960-86; y e a r o f f i r s t r e p o r t o f r e s i s t a n c e t o e a c h i n s e c t i c i d e ; a n d i n c i d e n c e o f m a l a r i a b a s e d on SPR* (= % s l i d e p o s i t i v i t y r a t e ) . (Compiled from o f f i c i a l d a t a , Government o f P a k i s t a n ; r e p r o d u c e d by p e r m i s s i o n f r o m R e f . 62.)

16 r


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The Long I s l a n d c a s e i s a c l a s s i c i l l u s t r a t i o n o f many o f t h e f a c t o r s known t o enhance t h e development o f r e s i s t a n c e , i n c l u d i n g i n t e n s i v e commercial p r o d u c t i o n o f the i n s e c t s p r i n c i p a l h o s t s (potato, tomato, e g g p l a n t ) , a v e r y s m a l l number o f w i l d h o s t s (Solarium rostratum, S. dulcamara) o f f e r i n g only minimal o p p o r t u n i t i e s f o r a v o i d a n c e o f s e l e c t i o n on u n t r e a t e d r e f u g i a , and a relatively isolated island location. Organophosphate, c a r b a m a t e , and i n c e r t a i n c a s e s p y r e t h r o i d r e s i s t a n c e have been r e p o r t e d more r e c e n t l y f r o m a number o f n o r t h e a s t e r n U.S. l o c a t i o n s (1, 21, 22.) and e a s t e r n Canada (£&, H ) as w e l l as f r o m M i c h i g a n and W i s c o n s i n ( H o l l i n g w o r t h , R. M., M i c h i g a n S t a t e U n i v e r s i t y , East L a n s i n g , p e r s o n a l communication, 1988). Downloaded by UNIV QUEENSLAND on April 14, 2013 | http://pubs.acs.org Publication Date: February 23, 1990 | doi: 10.1021/bk-1990-0421.ch002

f

Developments i n R e s i s t a n c e t o P y r e t h r o i d s In view o f t h e importance attached t o t h e s y n t h e t i c p y r e t h r o i d s as "end o f t h e l i n e " c o n v e n t i o n a l i n s e c t i c i d e s , some r e c e n t s i g n i f i c a n t d e v e l o p m e n t s i n r e s i s t a n c e t o t h i s group a r e c o n s i d e r e d s e p a r a t e l y i n t h i s section. Pests of Cotton. In s e v e r a l c o u n t r i e s i n which p r i n c i p a l p e s t s o f c o t t o n s u c h as H e l i o t h i s armigera, H. virescens and Spodoptera l i t t o r a l i s have d e v e l o p e d r e s i s t a n c e t o many o f t h e c h e m i c a l s p r e v i o u s l y u s e d f o r c o n t r o l , p y r e t h r o i d s have assumed m a j o r i m p o r t a n c e . I n t h e U.S., t h e a n n u a l c o s t o f i n s e c t i c i d e s on c o t t o n i s e s t i m a t e d a t $200 m i l l i o n , o f w h i c h 46% i s s p e n t on p y r e t h r o i d s (42). The i m p o r t a n c e a t t a c h e d t o t h e p r e s e r v a t i o n o f p y r e t h r o i d e f f i c a c y i s apparent i n t h e i n t r o d u c t i o n o f p y r e t h r o i d r e s i s t a n c e management programs i n a number o f c o u n t r i e s . The f i r s t o f t h e s e , a s t a t e - d i r e c t e d program, i n i t i a t e d i n E g y p t i n 1978, r e s t r i c t s p y r e t h r o i d u s e t o a s i n g l e a p p l i c a t i o n p e r y e a r a g a i n s t 5. l i t t o r a l i s , on c o t t o n o n l y , and i n c l u d e s v a r i o u s s u p p l e m e n t a r y , i n t e g r a t e d p e s t management (IPM) measures a g a i n s t t h i s and o t h e r p e s t s . This strategy apparently continues t o function s u c c e s s f u l l y (4Ji) . An A u s t r a l i a n p r o g r a m (44) was i n i t i a t e d i n 1983 a f t e r t h e d i s c o v e r y o f emerging p y r e t h r o i d r e s i s t a n c e i n H. armigera a t E m e r a l d , C e n t r a l Q u e e n s l a n d (4JL) . The program l i m i t s t h e use o f p y r e t h r o i d s t o 3 a p p l i c a t i o n s o v e r a 42-day m i d - s e a s o n p e r i o d , l i m i t s e n d o s u l f a n t o e a r l y and m i d - s e a s o n s p r a y s o n l y , and i n c l u d e s a d d i t i o n a l IPM measures. Grower p a r t i c i p a t i o n , t h o u g h v o l u n t a r y , a p p e a r s t o be e x c e l l e n t (A2.) . T h i s s t r a t e g y , w h i c h i s d e s c r i b e d as "a d e l i c a t e b a l a n c e between p y r e t h r o i d r e s i s t a n c e and e n d o s u l f a n r e s i s t a n c e " , h a s been r u n n i n g s u c c e s s f u l l y f o r 5 c r o p s e a s o n s (£, 4 £ ) . I t i s f e a r e d , however, t h a t w i t h o u t new i n t e g r a t e d t e c h n o l o g i e s , t h e s t r a t e g y w i l l p r o b a b l y f a i l , due t o c o n t a m i n a t i o n o f t h e r e f u g i a t o t h e e x t e n t t h a t t h e y w i l l no l o n g e r be u s e f u l



2.

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27

as a s o u r c e o f d i l u t i o n b y s u s c e p t i b l e i n d i v i d u a l s (&, AS) . I n U.S. c o t t o n g r o w i n g a r e a s , c o n t r o l p r o b l e m s w i t h p y r e t h r o i d s a g a i n s t H. virescens were f i r s t d e t e c t e d i n C a l i f o r n i a i n 1979 (42,48.) and s u b s e q u e n t l y i n Texas (A3.) . S u r v e y s c o n d u c t e d i n 1986 u s i n g a v i a l b i o a s s a y t e s t o n adults, revealed a s i g n i f i c a n t decline i n s u s c e p t i b i l i t y t o p y r e t h r o i d s i n t h e B r a z o s R i v e r V a l l e y and t h e U v a l d e a r e a o f Texas, and l o w e r l e v e l s o f d e c l i n e i n p o r t i o n s o f M i s s i s s i p p i , A r k a n s a s and L o u i s i a n a (49-51). S i n c e 1986, because of concern over emerging r e s i s t a n c e , a p y r e t h r o i d r e s i s t a n c e management program has g r a d u a l l y e v o l v e d , w h i c h recommends a v o i d i n g e a r l y and l a t e s e a s o n use o f p y r e t h r o i d s (£H). As i n A u s t r a l i a the program i s v o l u n t a r y , b u t l e s s v i g o r o u s i n d e t a i l , and a t p r e s e n t lacks a c e n t r a l resistance monitoring organization. Grower c o m p l i a n c e a p p e a r s t o be low b u t i m p r o v i n g (52). The c o n s e q u e n c e s o f l a c k o f g r o w e r c o m p l i a n c e a r e nowhere a s e v i d e n t a s i n T h a i l a n d where, d e s p i t e o f f i c i a l recommendations f o r m o d e r a t i o n i n t h e use o f p y r e t h r o i d s , a l a r g e number o f t r e a t m e n t s a r e a p p l i e d a n n u a l l y on cotton. I t has been e s t i m a t e d t h a t a t l e a s t 34% o f t h e t o t a l p r o d u c t i o n c o s t i s s p e n t on i n s e c t i c i d e s f o r b o l l w o r m (H. armigera) c o n t r o l . P y r e t h r o i d s were i n t r o d u c e d f o r b o l l w o r m c o n t r o l i n 1976 and r a p i d l y became p o p u l a r , b u t e v i d e n c e o f r e s i s t a n c e was d e t e c t e d a s e a r l y as 1979 (53.) . By 1986, broad spectrum p y r e t h r o i d resistance i n v o l v i n g fenvalerate, cypermethrin, c y f l u t h r i n and d e l t a m e t h r i n , o c c u r r e d w i d e l y (Wangboonkong, S., T h a i l a n d Department o f A g r i c u l t u r e , Bangkok, p e r s o n a l c o m m u n i c a t i o n , 1987). A v a i l a b l e d a t a on c o n t r o l e f f i c a c y r e v e a l a t e x t b o o k - l i k e pattern of d e c l i n e of e f f e c t i v e n e s s o f p y r e t h r o i d s a s dosages were i n c r e a s e d i n a p p a r e n t l y u n s u c c e s s f u l a t t e m p t s t o cope w i t h r e s i s t a n c e ( F i g u r e 3). Cockroaches. I n s e c t i c i d e r e s i s t a n c e i n cockroaches, t h o u g h a l o n g - s t a n d i n g p r o b l e m , has assumed g r e a t e r prominence i n recent years because of i n c r e a s e s i n the numbers o f e a t i n g e s t a b l i s h m e n t s and single-occupant apartments, which provide greater o p p o r t u n i t i e s f o r increases i n cockroach populations. Many o f t h e s e s i t e s are under r o u t i n e , commercial treatment b y i n s e c t i c i d e s , w h i c h enhances t h e r i s k f o r r e s i s t a n c e , e s p e c i a l l y i n t h e f a s t - b r e e d i n g German c o c k r o a c h , B l a t t e l l a germanica. A c o u n t r y w i d e s u r v e y i n t h e U.S. d u r i n g 1981-87 i n v o l v i n g 45 c o l l e c t i o n s , and u s i n g a minimum LT50 knockdown t h r e s h o l d as c r i t e r i o n f o r r e s i s t a n c e , has r e v e a l e d w i d e s p r e a d r e s i s t a n c e t o t h e c a r b a m a t e s p r o p o x u r and b e n d i o c a r b i n 50% and 75% o f t h e s t r a i n s , r e s p e c t i v e l y , and r e s i s t a n c e t o t h e o r g a n o p h o s p h a t e s c h l o r p y r i f o s , d i a z i n o n and m a l a t h i o n i n 7%, 13% and 80% o f t h e s t r a i n s , r e s p e c t i v e l y (54). A l s o of s i g n i f i c a n c e i s the evidence f o r r e s i s t a n c e to pyrethroids. I t was shown a s e a r l y a s 1956 t h a t some s t r a i n s o f B. germanica were r e s i s t a n t t o n a t u r a l


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YEAR F i g u r e 3. D e c l i n e i n f e n v a l e r a t e ( t o p ) and c y p e r m e t h r i n (below) e f f i c a c y a g a i n s t H e l i o t h i s armiger on c o t t o n , and dosages o f i n s e c t i c i d e a p p l i e d , 1976-86. ( C o m p i l e d f r o m d a t a p r o v i d e d by Wangboonkong, S., T h a i l a n d Department o f A g r i c u l t u r e , Bangkok, 1987.)



2.

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p y r e t h r i n s (55, 5&) . The p r e s e n t s u r v e y has shown r e s i s t a n c e t o p y r e t h r i n s i n 51% o f t h e c o l l e c t i o n s , t o a l l e t h r i n i n 18%, and v a r y i n g l e v e l s and f r e q u e n c i e s o f r e s i s t a n c e t o p y r e t h r o i d s (e.g. p h e n o t h r i n i n 13% o f t h e s t r a i n s , p e r m e t h r i n 9%, f e n v a l e r a t e 9%, and c y f l u t h r i n 2%) . A l t h o u g h t h e mechanisms o f r e s i s t a n c e t o p y r e t h r o i d s i n t h e s e s t r a i n s has n o t been i n v e s t i g a t e d , i t i s important to note that i n c e r t a i n s t r a i n s high r e s i s t a n c e t o p y r e t h r i n s (>100x) and a l l e t h r i n (>190x) i n c l u d e s o n l y m i n i m a l r e s i s t a n c e t o p y r e t h r o i d s ( p e r m e t h r i n (1.9x) a n d phenothrin (2.5x). H i g h r e s i s t a n c e t o p e r m e t h r i n (>120x) and p h e n o t h r i n (>140x), however, a l s o i n v o l v e s low t o moderate r e s i s t a n c e t o o t h e r p y r e t h r o i d s ( f e n v a l e r a t e 7.1x, c y f l u t h r i n 5.4x) (5A) . These v a r i a t i o n s i n r e s i s t a n c e spectrum would suggest t h a t metabolic, as w e l l as n o n - m e t a b o l i c (kdr) mechanisms have been s e l e c t e d . The i n v o l v e m e n t o f k d r r e s i s t a n c e i s more c l e a r l y e v i d e n t i n a s t r a i n o f B. germanica f r o m Osaka, J a p a n , t h a t has been u n d e r f i e l d s e l e c t i o n b y p e r m e t h r i n . The s t r a i n has shown an e x t e n s i v e s p e c t r u m o f c r o s s r e s i s t a n c e i n v o l v i n g a l l s e v e n p y r e t h r o i d s t e s t e d and has y i e l d e d e l e c t r o p h y s i o l o g i c a l evidence of nerve i n s e n s i t i v i t y t o the a c t i o n o f p y r e t h r o i d s (52.) . The U.S. s u r v e y p r o v i d e s e m p i r i c a l s u p p o r t o f t h e importance of p o p u l a t i o n i s o l a t i o n as a f a c t o r enhancing the e f f e c t i v e n e s s of s e l e c t i o n f o r r e s i s t a n c e : pyrethroid r e s i s t a n c e was e v i d e n t m a i n l y i n p o p u l a t i o n s o b t a i n e d from n a v a l v e s s e l s and a mess h a l l t h a t were u n d e r i n t e n s i v e p y r e t h r o i d t r e a t m e n t (Cochran, D.G., V i r g i n i a P o l y t e c h n i c I n s t , and S t a t e U n i v . , B l a c k s b u r g , p e r s o n a l c o m m u n i c a t i o n , 1988). Horn f l y . The r a p i d i t y o f t o x i c a c t i o n o f p y r e t h r o i d s , complemented b y a d e g r e e o f r e p e l l e n c y , has l e d t o t h e i n t r o d u c t i o n of pyrethroid-impregnated ear tags f o r c o n t r o l o f h o r n f l i e s (Haematobia i r r i t a n s ) on c a t t l e . I t was hoped t h a t s u c h t o p i c a l use o f p y r e t h r o i d s w o u l d h i n d e r development o f r e s i s t a n c e b y a l l o w i n g some i n s e c t s t o r e m a i n unexposed. However, t h e w i d e s p r e a d use o f t h i s s i m p l e method, and t h e s e a s o n - l o n g e f f e c t i v e n e s s o f t h e e a r t a g s (£3.), e q u i v a l e n t t o 10-14 g e n e r a t i o n s (52) , l e d t o s e l e c t i o n o f r e s i s t a n t populations w i t h i n the r e l a t i v e l y b r i e f p e r i o d o f two y e a r s , f i r s t i n F l o r i d a i n 1982, and i n 14 o t h e r s t a t e s b y 1985 (52.) . The w i d e s p e c t r u m o f p y r e t h r o i d r e s i s t a n c e i n t h e s e populations, which involves permethrin, f e n v a l e r a t e , f l u c y t h r i n a t e , cypermethrin, d e l t a m e t h r i n , and c y h a l o t h r i n , t h e r e l a t i v e l a c k o f s y n e r g i s m b y p. b . (££) o r DEF, and t h e p r e s e n c e o f DDT a s w e l l a s m e t h o x y c h l o r r e s i s t a n c e (52), s u g g e s t t h a t t h i s r e s i s t a n c e i s due t o t h e s i t e i n s e n s i t i v i t y mechanism kdr. I n t e r e s t i n g l y , some e v i d e n c e o f b e h a v i o r a l r e s i s t a n c e was a l s o d e t e c t e d . I t was o b s e r v e d t h a t p y r e t h r o i d - r e s i s t a n t f l i e s t e n d e d t o


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RESISTANCE TO

AGROCHEMICALS

f r e q u e n t t h e u n t r e a t e d v e n t r a l and p o s t e r i o r r e g i o n o f t a g g e d c a t t l e , a b e h a v i o r t h a t t e n d e d t o p e r s i s t even i n the absence o f the i n s e c t i c i d e s t i m u l u s (£1).


Developments i n R e s i s t a n c e t o B i o p e s t i c i d e s B i o p e s t i c i d e s , as r e p r e s e n t e d by i n s e c t i c i d a l l y a c t i v e t o x i n s p r o d u c e d by v a r i o u s b a c t e r i a , e.g. BT and o t h e r o r g a n i s m s , have been i n c o m m e r c i a l use f o r n e a r l y two d e c a d e s ; however, no i n f o r m a t i o n i s a v a i l a b l e c o n c e r n i n g t h e mechanisms o f p o t e n t i a l r e s i s t a n c e i n t a r g e t p o p u l a t i o n s . The a v a i l a b l e r e p o r t s r e v e a l no c o n s i s t e n t p a t t e r n o f r e s p o n s e t o s e l e c t i o n and may s u g g e s t t h a t s e v e r a l mechanisms, some o f them u n i q u e , may d e t e r m i n e t h e r i s k f o r r e s i s t a n c e i n any i n s e c t - s p e c i e s / B t - s t r a i n combination Q ) . L a b o r a t o r y s e l e c t i o n s o f house f l i e s and Drosophila melanogaster by BT p - e x o t o x i n p r o d u c e d r e s i s t a n c e s l o w l y and o f low l e v e l s ( PERMETHRIN (Musco)

METHO^RENE 8 o

Overview of Insecticide Resistance - ACS Symposium Series (ACS

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