50 PROTECTION OF PLANTS — 1922-23 



The study as we undertook it was really quite simple in as much as we 

 only followed the idea of watching the plants closely for considerable periods 

 at a time and noting the various insects which alighted upon the seed heads 

 of the various crops. The specimens were also collected for later determination 

 and percentages from captured material as well as from observational matter 

 were built up. In the majority of cases the insects taken were examined 

 under binoculars to determine whether or not pollen grains were adhering to 

 their bodies. An endeavor was made also to conduct this work over a period 

 of two or three months which meant that a certain number of days at periodic 

 intervals were set apart for close observation while, on other days, only cursory 

 observations were made. You will agree, of course, that this method was very 

 haphazard but as it turned out we obtained the practical information which 

 we were after. As you will see by the records that I propose to give you in 

 a moment or two that the honey bee entered into the situation in every case 

 and as the honey bee is not only the most diligent collector of pollen and nectar 

 but also the strongest flier it practically eliminated all other insect visitors. 



Mangels. 



It has been stated by some authorities that the flowers of the field mangel 

 is not visited by honey bees. This we can say is not correct. We must 

 remember that the question of the available honey flow in a given district 

 bears upon the point as to what insects visit flower heads of any particular 

 kind. I do not doubt for a moment that if the country at any particular time 

 of year is well supplied with flowering plants the honey bee would not be a 

 factor in the pollination of mangels, but if the flow is light there is no question 

 at all but that the honey bee will visit mangel heads. Over a period of two 

 months the following average of insect visitors was determined. 



/o 



Syrphids 

 Solitary bees 



Hemiptera 8% 



Honey bees 7% 



Coleoptera 2% 



Wasps 2% 



We will have more to say upon the actual habits of these various insect 

 in a moment or so. 



Wind is a factor that must be considered in the carrying of mangel pollen 

 just in the same way as wind is probably a prime factor in the carrying of corn 

 pollen. Quite apart, therefore, from the question of insect visitors a proper 

 regard must be taken of the question of prevailing winds when setting out 

 fields of mangels for seed production. The flowers are small but they have 



