Use the stated field conditions to suggest a mechanistic limitation, or convert volume and concentration before calculating and describing the required solution mass.
The photograph shows a fruit fly, Drosophila suzukii, on the skin of a fruit.
This species of fruit fly is endemic to southeast Asia but recently it has become an invasive species in Europe.
The female lays fertilised eggs under the skin of fruits.
The eggs hatch into larvae that feed on the fruit.
The larvae develop into pupae that become adult flies.
A student investigated the effect of using an organic pesticide, pyrethrum, on the hatching of eggs and the development of pupae.
Sixteen flasks containing a culture medium were prepared. Eight flasks had 0.5 g of pyrethrum added.
Each flask had one female fly that layed eggs for 24 hours. The fly was then removed and the eggs were allowed to hatch and develop into pupae.
The photograph shows fly pupae in one of the flasks.
After five days, the number of pupae in each flask was counted.
The results were:
Number of pupae from untreated culture medium ( A )
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Number of pupae from treated culture medium (B)
Pyrethrum is applied to fruit crops growing in fields.
Suggest two reasons why applying pyrethrum to fruit crops in fields might not reduce damage to fruits.