Life Cycle and Ovipositional Preference of Asian Papaya Fruit Fly (Bactrocera Papayae Drew & Hancock) for Guava (Psidium Guajaya, L.)

Asian papaya fruit fly Bactrocera papayae is one of the insects’ pest that is very destructive and causing severe damage to guava, Psidium guajava, Linn. Details on B. papayae are still lacking compared to the other species such as B. carambolae and B. cucurbitae. This study was conducted to determine the number of larval instars, the life cycle and ovipositional preference of the B. papayae on guava. Result showed that the B. papayae underwent three larval instars which can be determined by morphometric characters of the length and width of the larvae’s bodies. The body length for the first, second and third instars were 1.27 ± 0.03, 4.33 ± 0.05 and 7.84 ± 0.07 mm respectively, whilst the width for the body were 0.23 ± 0.01, 1.04 ± 0.01 and 1.85 ± 0.03 mm respectively. Moulting took one day for each larval instar. In the life cycle study, the percentage of individuals survived decreased as the stages changed from egg until adult. Findings showed that the eggs hatched after 1.16 days. Larvae underwent three instars and survived for 12.02 ± 0.13 days before entering the pupal stage. Pupae collected emerged as the adults after 7.03 ± 0.08 days. It was observed that the longevity of the adult male B. papayae was not significantly (P>0.05) different compared to the female adult. The ovipositional preference could be determined by investigating the number of larvae laid by single female per guava. Bactrocera papayae female was observed preferred to oviposit on the mature guavas in both choice and no-choice experiments. There was no significantly different between the numbers of ovipositional punctures made and larvae laid on guavas in the choice and no-choice experiments. There was a significantly different (P<0.05) in the number of larvae obtained at different maturity stages in both choice and no-choice experiments. In the choice and no-choice experiments, the numbers of larvae observed were comparatively higher in more ripened guavas than less ripened ones. This indicated that mature guavas provide more needs and nutrients required by the larvae to gro

Determination of larval instar of Bactrocera papayae (Diptera : Tephritidae) on guava, Psidium guajava, Linn. based on morphometric characters

Morphometric characters such as length and width of the Bactrocera papayae larvae could be used to determine the larval instars at their immature stage. Observation in this study indicated that B. papayae underwent three larval instars. The duration for the first instar, second and third instar was 4,4 and 7 days respectively. There was a significant difference in the length and width within larval instars of B. papayae. After hatching, the length of the larvae was 1.04 mm and the longest could reach up to 8.32 mm while the width starts from 0.18 mm and could reach up to 2.08 mm before completing all instars during the immature stage. Means length of the larvae were 1.27 ± 0.03, 4.33 ± 0.05 and 7.84 ± 0.07 mm whilst means width were 0.23 ± 0.01, 1.04 ± 0.01 and 1.85 ± 0.03 mm for the first instar, second instar and third instar respectively. Moulting process of the larvae occurred twice between day-4 and day-5 and also between day- 8 and day-9

Growth and development of Bactrocera papayae (Drew & Hancock) feeding on guava fruits

Asian Papaya Fruit Fly, B. papayae (Drew & Hancock) undergoes four stages (egg, larva, pupa and adult) during its growth and development. In this study, observation showed that the egg's stage took 1.16 ± 0.00, larva's stage took 12.02 ± 0.13 and pupa's stage took 7.03 ± 0.08 days before the emergence of the adults. The male adult survived for 21.97 ± 2.69 days whilst the female 19.19 ± 1.50 days. It was observed that the eggs laid in a cluster, range between 10 - 50 eggs per cluster. The length and width of the individual egg observed were 1.12 ± 0.03 mm and 0.20 ± 0.00 mm respectively. The percentages of the survived individual larva decreased from the first instar until third instar. In the observation, the length and width of the larva reached 7.77 ± 0.08 mm and 1.84 ± 0.03 mm respectively. Pupae were observed changing in colour from pale yellow to dark brown. The length and the width of the pupae observed were 6.78 ± 0.16 mm and 2.90 ± 0.02 mm. The longevity of the adult B. papayae (Drew & Hancock) was influenced by the diets they consumed, the presence of other individuals, wideness of the areas, differences in times taken in different stages and temperature in the laboratory

Effects of harvesting Mucuna bracteata on the legume biomass and soil properties under mature oil palm

The under-utilized legume Mucuna bracteata is a potential biomass resource in Malaysia. A 24-month study was conducted under 10-year-old mature oil palm trees to determine the effects of several harvesting frequencies of M. bracteata on the legume biomass and soil properties. The experimental design was a randomized complete block design (RCBD) for the biomass and a two-factorial RCBD for the soil properties. The treatments were the harvesting frequencies, which were once every two, four, six, and twelve months. The control treatment was without harvest. There were significant effects on the legume’s cumulative biomass, standing biomass, leaf area, nutrient contents, and total nutrient harvested for N, Ca, Mg, and cellulose content. Generally, the more frequent the harvest, the more biomass was obtained, but the more legume standing biomass and leaf area were reduced. Despite the reduction in legume growth and leaf area in the field, harvesting the legume did not affect any of the soil physicochemical properties. The biomass N, Ca, and Mg contents and nutrient harvested were also affected by harvesting. This was due to the production of relatively more young shoots after harvesting, which would remove most of the aboveground plant parts. The cellulose content in the legume also increased for the same reasons. Results showed that harvesting M. bracteata once every six months was an acceptable compromise between collecting large amounts of legume biomass and having a reduced legume growth recovery and leaf area in the field, but yet not detrimentally affecting the soil properties