2. Direct contact with pesticfde during application. Adult 

 field bees are primarily affected but brood may be, from 

 neglect — starvation or exposure to extremes of tempera- 

 ture. 



3. Exposure to pesticides having prolonged residual action. 

 In some instances heavy mortalities have resulted from 

 exposure to residues on leaves, twigs, or blossoms on 

 which bees may crawl or rest. 



Comparative Toxicity of Pesticides to Honey Bees : 



Anderson and Atkins, 1967, University of California, have 

 conducted exhaustive studies on the relative toxicity of pesticides 

 to honey bees. Some of the investigations have been conducted in 

 the field and some are laboratory studies. On the basis of their 

 work, they classify the toxicity of pesticides to honey bees in 

 three groups; Highly toxic. Moderately toxic and Relatively non- 

 toxic. It must be remembered that the effects of weather on pesti- 

 cides may influence the toxicity of the material to insects so that 

 some of the results reported for California might not be the same 

 as would be the results here in New England. 



The comparison that follows of the toxicities of pesticides 

 to honey bees is taken verbatim from Anderson and Atkins, 1967, 

 Toxicity of Pesticides and Other Agricultural Chemicals to Honey 

 Bees (University of California Extension Publication AXT-251). 



Table 1. Relative toxicity of pesticides to honey bees as deter- 

 mined by laboratory and field tests in California (1950- 

 1966). 



GROUP 1 



HIGHLY TOXIC: 



Severe losses may be expected if the fol- 

 lowing materials are used when bees are 

 present at treatment time or within a day 

 thereafter, except as indicated by foot- 

 notes . 



a 1 d r i n -, p 

 arsenicals ' 

 Azodrin R 



(crotonami de) ' 

 Baygon R 

 Baytex R 



(f enthi on) 

 BHC"^ , , 

 Bidrin R ' '^ 

 Bomyl R 

 Chlorthion R 

 Cygon R ^ 



(dimethoate) 

 D a s a n i t R 

 DDVP 



(dichl orvos ) 



diazinon 

 Dibrom Rp ^ 



(naled) ' 

 dicapthoR 

 d i e 1 d r i n 

 Dimecron R p 



(phosphami don) 

 Dursban R 

 epn' '^ 

 Ethyl Guthion R 



(azi nphosethyl ) 

 Famophos R 



(f amphuri 

 Furadan Rp 

 Gardona R 



Guthion R 



Cazinphosmethyl ) 

 heptachlor 

 Imidan R 

 Isolan R 

 lindane p . 

 malathion ' 

 Matacil R 

 Mesural R 

 Metacide R 

 methyl parathion 

 Methyl Trithion 

 Mobam R , p 

 parathion ' 

 Phosdrin R -i p 3 



(mevi nphos ) ' ''^' 



,1 



1,2 



