Turnip weed

Rapistrum rugosum





Turnip weed is a winter and spring flowering annual weed which grows on the black soil plains and agricultural lands of North West NSW and South West Queensland. It is extensively used for breeding bees in the spring.

Turnip weed's pollen has a crude protein level of 24% to 25%. Kleinschmidt (1984) indicated a higher crude protein level of 25% to 29_%. It is very highly digestible, with all essential amino-acids well represented (Table 23). Although protein quality can vary from place to place. On the whole turnip weed pollen is very good for bee breeding. Bees breed so well on it they often swarm.

Bees that have bred on turnip weed pollen for four to six weeks (if they have not swarmed themselves out) should be able to work heavy honey flows. But for some reason this is not always the case. Body-protein should be high and their ability to work should be good. However the tendency to swarm while working turnip weed may render this floral source less useful than the protein analysis may suggest. Experienced beekeepers do not keep their bees on turnip weed for more than six weeks, so as not to over-stimulate the bees.

Turnip weed pollen is good to collect and store for feedback to the bees.

Turnip weed does not produce nectar in cold weather yet it can produce good volumes of pollen. It is only when the weather warms up that it produces nectar. Feeding sugar syrup to the bees when there is no nectar productiowill help them to breed rapidly.

Queen bees bred on turnip weed are not always good quality, although there have been reports of good queens bred on turnip weed when sugar syrup is fed to the cell builders. (Campbell, personal comment) This is especially when it is still cool, and the turnip has not started to produce nectar.

Table 23: Turnip weed Rapistrum rugosum


Amino-acid
Minimum % of Amino-Acid from De Groot (1953)
Moree

Spring 1988

Moree

Spring 1992

Threonine 3.0 4.59 4.1
Valine 4.0 4.38 4.6
Methionine 1.5 1.72 2.2
Leucine 4.5 6.78 6.0
Iso-leucine 4.0 3.84* 4.2
Phenylalanine 2.5 4.07 3.7
Lysine 3.0 7.87 6.2
Histicine 1.5 2.69 2.1
Arginine 3.0 5.85 5.6
Tryptophan 1.0 - -
Crude Protein - 25.3% 24.4%

* Low level of this amino-acid
 
 

Turnip weed pollen seen under a microscope (X400)



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