Page 10 17. The smaller tea tortrix (Adoxophyes honmai) is a moth that is an economically important pest of tea plants in Japan. A honmai has a number of development stages (larvae) from egg to adult. Viruses that infect crop pests have potential use in controlling pest populations. A study compared the infection and killing of A honmai by two viruses, X and Y. Mean survival time after infection for each larval stage was measured and the results are shown in the table. Uninfected larvae were then released onto tea plants that had either virus X, virus Y or no virus applied to their leaves. The percentage infection of the larvae was measured and the results are shown in the graph. Stage of insect development when infected Mean survival time ± SE (days) Virus X infection Virus Y infection 1st 18·9 ± 0·6 5·8 ± 0·1 2nd 15·2 ± 0·4 7·0 ± 0·1 3rd 12·2 ± 0·2 7·0 ± 0·1 4th 10·1 ± 0·2 8·0 ± 0·1 5th 8·0 ± 0·1 6·9 ± 0·1 15 10 5 0 Virus X Virus Y No virus Treatment Percentage infection of larvae Which of the following conclusions can be drawn from this information? A Virus X has a higher transmission rate and is more virulent than Virus Y. B Virus X has a higher transmission rate and is less virulent than Virus Y. C Virus X has a lower transmission rate and is less virulent than Virus Y. D Virus X has a lower transmission rate and is more virulent than Virus Y.