Ovipositional Behaviour Preference of Oriental Fruit Fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae) on Different Host Fruits

The oriental fruit fly Bactrocera dorsalis Hendel (Diptera: Tephritidae), is a polyphagous insect pest that gives severe damage to orchard fruits when the female adults lay their eggs into the fruits. However, the damage can be reduced by manipulating the behavior of this female insect. Thus, this study aimed to determine the ovipositional  preference behavior  of B. dorsalis on different host fruits. The experiment set up was laboratory-based ‘no-choice’ and ‘choice’ of oviposition behavior by the insect. The parameter recorded were the number of fruit visit, duration of fruit visit, number of attempted to oviposit, number of ovipositing and duration of oviposition completed. Guava (Psidium guajava L), mango (Mangifera indica L.) and papaya (Carica papaya L.) were used as host fruits. In the no-choice experiments, the host fruits significantly influenced the number of fruit visit and duration of the visit of B. dorsalis female. The most fruit visited by B. dorsalis female was mango compared to other host fruits whilst papaya shows the longest duration of the host fruit visit by B. dorsalis. Although the characteristics of host fruits differs, the number and duration of oviposition by B. dorsalis shows no significant difference among the host fruits and no activity of oviposition was recorded on guava fruit. When given a choice of different host fruits, the duration of fruit visit and number of attempt to oviposit by B. dorsalis significantly differed among host fruits. However, the host fruits does not influenced the number of fruit visit, number of oviposit and duration of oviposition completed. Interestingly, only guava shows the egg oviposition activity by B. dorsalis females whilst no oviposition behaviour was observed on mango and papaya. Results obtained in this study will benefit the study of insect pest behaviour which then can be use in biological control program in order to reduce the agriculture damage

Potential of Pseudomonas sp. & Bacillus sp. for Controlling Fusarium oxysporum, A Causal Agent For Rockmelon Fusarium Wilt Disease

Fusarium sp. recognized as among main pathogen to the rockmelon. The disease was renown as Fusarium wilt disease (FWD). As to the FWD, objectives of this study were to obtain the pure culture of Fusarium oxyporum f. sp. melonis (Fom), and to control the Fom via biological control method using effective bacteria. Beside, the study was also screened the plant growth promoting properties of Pseudomonas sp. and Bacillus sp.. Fusarium oxysporum f. sp. melonis Snyder & Hans caused postharvest disease problem affecting melon production and loss almost 100 % due to this destructive disease. Effective bacteria like Bacillus sp. and Pseudomonas sp. has a good potential to suppress growth of pathogen. Based on the phenotypic identification and morphological characterization of fungus isolated was identified as Fusarium oxysporum f. sp. melonis and it was than confirmed with molecular methods with 99% similarity. Environmental factors that give the optimum growth of Fusarium were evaluated. Based on the result, the growth of fungus showed the best on PDA media (2.538 ± 0.095 cm), 30 °C (2.475 ± 0.096 cm), pH 4 (2.700 ± 0.216 cm) and under continuous dark condition (3.433 ± 0.115 cm). The Bacillus sp. (DP - 1) showed the highest antagonistic activity of fungus and bacteria with 70.68 % in dual culture assay and highest inhibition of fungus growth in double layer test with no ability to growth. As production of protease, all 7 bacteria tested showed positive result of by producing clear zone on PDA media except by B43. From several parameter tested, the result showed that Bacillus sp. has more potential as biological control agent to control the Fusarium wilt disease in rockmelon plant compared to Pseudomonas sp.

Potential of Pseudomonas sp. (UniSZA-MKB10) and Bacillus spp. (UniSZA-BK3, UniSZA-BK4 and UniSZA-DA) as Biological Control Agent for Controlling Anthracnose Disease of Carica papaya L.

Colletotrichum gleosporioides is known as the causal agent of anthracnose disease of Carica papaya in Malaysia. Economic losses are mostly reported during postharvest where the disease incidence and severity was recorded as 90-98 % and 25-38 % respectively. Colletotrichum sp. were isolated from lesions of infected C. papay that showing the typical anthracnose disease symptoms. Three types of fungal cultures were obtained and identified as Colletotrichum sp., Fusarium sp. and Rhizoctonia sp. One of the fungal obtained that was confirmed to be C. gleosporioides is based on morphological characteristics on PDA and  Koch’s Postulate has confirmed C. gleosporioides as causal agent of papaya antracnose disease. The pathogen under study varied in its ability to grow under different environmental conditions. However, isolate preferred temperature range of 20°C to 30°C for the growth on PDA media. C. gloeosporioides isolates grew well at pH values within range of pH 6 to pH 7. Four bacterial strains, UniSZA-MKB10, UniZA-BK4, UniSZA-BK3 and UniSZA-DA, were tested in this study and proved to have antifungal properties against C. gloeosporioides. Dual culture assay, double layer and double plate method were conducted to test their metabolites as well as diffusible and volatiles antibiotic compound of bacteria. Out of four, three bacterial were found to show inhibition ability with MKB10 showed highest percentage of inhibition on radial growth with 62.08 ± 3.64% PIRG as well as produced greater diffusible and volatiles substances that significantly (P<0.05) inhibited the mycelial growth of C. gloeosporioides with PIRG of 85.48 ± 1.53 % and 31.03 ± 2.56 % respectively, and followed by UniSZA-DA. Culture filtrate of BK4 also showed highest significance effect towards inhibition of spore germination where the germ tube produced is the shortest (0.9055 µm) 

Potential of Exserohiulm monoceras as bioherbicide for controlling Echinocloa crus-galli (Rumput Sambau).

The fungus isolated from diseased Echinochloa crus-galli was identified as Exserohilum monoceras, based on the conidial morphology, germination characteristics and hilum morphology. The objectives of this study were to screen and isolate fungal pathogen of E. monoceras from infected E. crus-galli as well as to determine the pathogenicity of E. monoceras and the optimum conditions for growth and sporulation of E. monoceras. In repeated trials, the pathogenicity of this fungus to its host was confirmed by Koch’s postulate. The pathogen caused a high level of disease on E. crus-galli where symptoms appeared within 24 h of inoculation. It induced eyespot lesions typical of infection by Exserohilum spp. and induced a severe ‘burnt’ appearance on the foliage of E. crus-galli. The leaf tissues in the vicinity of heavy infestation were completely killed. The disease did not develop on non-inoculated plants, which was indicative of localized infection and lack of significant secondary disease cycles. The laboratory study indicated that better growth and appressoria production can be attained when the fungus is exposed to temperature in the range of 25 to 30 oC. This study also indicated that Maxigreen®, which is an adjuvant, when mixed with sunflower in the ratio of 0:5:7 is ideal for formulating the conidia. This research has illustrated that solid media such as agar is an excellent growth media, but spore production has been influenced by the nutrient content of the media. The best medium for sporulation was half strength V8 juice agar

Comparison on the effect of treatment and subculturing on shoot regeneration from shoot tip seedlings of Psidium guajava L. var. Beaumont

An experiment was carried out in order to study the effect of treatment containing 0.5 and 1.0 mg/L 6-benzylaminopurine (BAP) and effect of subculture on percentage of shoot formation, number of shoot per explant and mean shoot height of shoot tip explant of Psidium guajava L. var. Beaumont. MS medium (Murashige and Skoog, 1962) was used with 30 g/L of sucrose and 7 g/L agar type 900. Shoot tips of elongated shoots were decapitated to abolish its apical dominance prior to sub-culturing was carried out to a fresh medium every 4 weeks. The increase in mean number of shoots per explant and the shoot height was observed for every subculture. Treatment 1.0 mg/L BAP in comparison to treatment 0.5 mg/L BAP showed higher mean number of shoot per explant per subculture whereas treatment 0.5 mg/L BAP showed higher mean shoot height per subculture. Data were analyzed using T-test until the fifth subculture