| 摘要： ‘珍珠拔’番石榴果實(Psidium guajava L. ‘Jen-Ju Bar’)栽培上受東方果實蠅(Bactrocera dorsalis Hendel)為害，現行所採用之防治方式中以套袋防治最為廣泛，套袋影響果實發育與品質。調查夏季果實發育期受東方果實蠅為害時期，以開花後時間而論，於開花後第11週起，易受東方果實蠅為害，於花後第13週，果實發育進入第三階段快速生長期，為害率顯著增加；以果實大小調查受東方果實蠅為害情形，除少數發育不良提早轉色軟化之果實外，果實直徑4 cm以下，受東方果實蠅為害風險極微；果實以人工接種東方果實蠅蟲卵及放置於東方果實蠅成蟲飼育箱內，亦顯示直徑4 cm以下之果實，不利於東方果實蠅生長發育。另一方面，於開花後4週內套袋，會提高套袋內果實落果率。 東方果實蠅產卵偏好主要受寄主果實之顏色、硬度、氣味及成分等因素影響，分析不同發育期‘珍珠拔’番石榴果實外部形態、內部營養及酚類化合物等，探討果實受東方果實蠅為害可能因子，顯示，澱粉含量及總酚類化合物與東方果實蠅產卵偏好無顯著差異，而易遭受為害之果實，果實色澤較為淡黃、果實硬度及可溶性單寧含量呈顯著下降、全可溶性糖及葡萄糖、果糖及蔗糖類含量則顯著增加。以固相微量萃取法和氣相質譜儀分析田間不受東方果實蠅為害之幼果、易受為害之成熟果、已受東方果實蠅為害之被害果、以及枝條和葉片之揮發性成分，共鑑定45種化合物，其中β-石竹烯(β-caryophyllene)，檸檬烯(limonene)，乙酸（Z）-3-己烯酯((Z)-3-hexenyl acetate)，乙酸乙酯(ethyl acetate)，乙酸異戊酯(isopentyl acetate)，乙酸異丁酯(isobutyl acetate)和乙酸己酯(hexyl acetate)7種化合物，研究顯示對東方果實蠅具有吸引力；其中β-石竹烯和檸檬烯在枝條、葉片和未成熟果實己具有高的含量，但這些組織是不受東方果實蠅為害，而乙酸乙酯、乙酸異戊酯、乙酸異丁酯和乙酸己酯僅在已被東方果實蠅為害之被害果實中檢測出，惟乙酸（Z）-3-己烯酯在成熟果及受果實蠅為害果實有較高含量，此化合物可能與東方果實蠅選擇寄主果實有關。 ‘珍珠拔’番石榴果實發育至第三階段快速生長期，其醣類含量顯著增加，此階段亦是，易受東方果實蠅產卵為害時期，探討醣類含量對果實蠅幼蟲存活影響，結果顯示，以4種不同發育期果實之果泥飼育東方果實蠅幼蟲，皆可使幼蟲發育至成蟲，存活率隨著果實發育成熟度而增加，未成熟果實添加不同濃度之蔗糖，幼蟲存活率隨著濃度增加而提高之趨勢。以添加10%濃度之葡萄糖、果糖、蔗糖溶液和3種混合液於未成熟番石榴果泥中，比較對幼蟲存活影響，顯示，4種溶液對幼蟲存活率無顯著差異。果實直徑在4 cm以下，於田間調查及人工接卵試驗上，受東方果實蠅為害風險極微及不利其幼蟲存活，惟於本試驗，將果肉攪碎加水後飼育果實蠅，顯示在果實直徑3 cm以下具有35.5%存活率，推論，果樹上之未成熟果實不受果實蠅為害，可能與果皮硬度相關，因幼果果實質地較硬，果實蠅產卵管無法插入；人工接卵時，於未成熟果實內幼蟲無法存活則可能與果肉硬度及含水量有關。 套袋改變果實發育環境，影響果實生長速率與品質。以果實發育期不受果實蠅為害時期內，分開花後第4、6、8及10週4個時期套袋，分析不同套袋及採收時間之果實硬度、色澤、可溶性固形物及抗壞血酸含量等，探討不同套袋時間對採收後果實發育之影響。結果顯示，於花後第4週套袋之果實，較為早熟但其果皮較為黃化及體積偏小現象；花後第8-10週套袋之果實，果實較為晚熟，果實硬度較高。較早套袋雖可加速果實成熟，但考量較早套袋對於果實發育生理性狀較不明顯，不易於疏果、選果作業，可於花後第6-10週進行套袋，亦能有效防止果實蠅為害。臺灣夏季高溫多濕，此環境氣候使得果實生長速率遠大於冬季果實，亦造成果實品質較差，質地較易軟化等，為維持夏季產番石榴果實品質，有多種栽培操作方式，如修剪枝葉、疏果、施肥、不同套袋材質使用及調節產期等。本研究結果，認為調整套袋時間亦是一個值得推薦的方式，於開花後第6週至第10週期間，再進行選果套袋作業，較為方便擇優選果及套袋、果實有較佳硬度及較長的發育期，對於果實營養物質的累積及貯藏品質應有較好的表現。In guava (Psidium guajava L. ‘Jen-Ju Bar’) cultivation, the fruit damaged by the oriental fruit fly (Bactrocera dorsalis Hendel) which is one of the major pests in fruit during development. In the cultivation to prevent the fruit flies damage, used bagging for fruit was the most widely method. In the field observation, was made to record the time of fruit infected by fruit flies at different growth of stages. The results showed that the summer fruits were to be infected with fruit flies during the 11th week after bloom. At the 13th week after bloom, fruit growth entered the rapid growth stage and the hazard ratio of fruits with fruit flies was significantly increased. Investigated the damage condition of guava fruit infested with fruit flies at different size, the exception of a few fruit disorder of growth, early turn color and softening, the diameter of less 4 cm of guava fruit , the risk of infested with fruit fly is minimal. Artificial infested with fly eggs to fruit and placed in Oriental fruit fly breeding box to investigate the infestation of guava fruits by oriental fruit fly, showed that the fruit diameter of less than 4 cm, is not conducive to fruit flies growth and development. Fruit flies ovipositional preference is affected by the color, hardness, odor and composition of the host. The investigated the changes in hardness, color, carbohydrates, phenolic compounds, and soluble tannins of fruits during different maturities, and explored their effects on oviposition of Oriental fruit fly. The results showed that there was no significant difference in color change, starch content, and total phenolic compounds between Oriental fruit fly whether oviposition or not. However, the fruit hardness and soluble tannin content were significantly reduced and the content of soluble sugar, glucose, fructose and sucrose increased significantly in fruits with Oriental fruit fly infected stage. Using Headspace Solid-Phase Microextraction (HS-SPME) and Gas Chromatography/Mass Spectrometry (GC/MS), the volatile compounds were analyzed from fruit (immature, mature and infested by fruit flies), stem, and leaf to determine which volatile compounds attract the fruit fly. A total of 45 compounds were identified, of which β-caryophyllene, limonene, (Z)-3-hexenyl acetate, ethyl acetate, isoamyl acetate, isobutyl acetate and hexyl acetate have been reported to have attractive effects. β-caryophyllene and limonene were produced at high levels from the stem, leaf and immature fruit, but these tissues were not infested by fruit fly. Ethyl acetate, isoamyl acetate, isobutyl acetate and hexyl acetate were only found in fruit infested by fruit fly. (Z)-3-hexenyl acetate had a high content in the mature fruit, the stage that is susceptible to fruit fly infection. The results suggest that the volatile (Z)-3-hexenyl acetate of the mature guava fruit was an important factor in attracting fruit flies to the choice host. When the Jen-Ju Bar guava fruit developed to the third phase of growth, its sugar content increased significantly, it is also a period of susceptible to oriental fruit fly infestation. To further investigate the effect of sugar content on the survival of fruit fly larvae, using guava pulp at 4 different fruit maturities as growth medium for breeding fruit flies, the survey showed that the larvae could survived to adults at all treatment, the survival percentage of larvae increases with fruit developmental maturity. Add different concentrations of sucrose to fruit, the survival ratio of fruit fly larvae also increased with the increase of the concentration. In the glucose, fructose, sucrose and three mixed solutions added to the pulp, the larvae survival percentage has no significantly. When the fruit maturity was below 4 cm in diameter, in the field investigation and artificial eggs oviposition test, fruit flies were not infected and unable to survive. However, in this experiment, in the crushed fruit puree and add water to feed fruit flies, showed that the fruit diameter of less than 3 cm had a survival ratio of 35.5%. It is inferred that unripe fruit not be infected by fruit flies, may be related to the hardness of the peel and fruit texture, the fruit flies can''t invade the oviposition. The inability of the artificial larvae to survive in the immature fruit may be related to the hardness and water content of the flesh. The bagging of fruits was change to fruit development environment, such as increasing relative humidity, reducing gas exchange and reduces the absorption of light source, affect fruit growth rate and quality. In this study, the fruit development period was divided into four time points at the fourth, sixth, eighth and tenth week after bloom, and the fruit hardness, color, ascorbic acid content and sweetness of the different bagging and harvesting time were analyzed to explore the impact of different bagging time on the quality of fruit after harvest. The results showed that, the fruits of bagging at the 4th week after bloom, the fruits were more mature but their peel color yellowing and small fruit size; the fruits of bagging at the 10th week after bloom were more late-maturing, there was no significant difference in the fruit size and quality between the earlier bagging, but the fruit had a higher hardness. Although early bagging can accelerate fruit ripening, but considered that the earlier bagging is less obvious for fruit development and physiological traits, and it is not easy for fruit thinning and fruit selection. In the cultivation and management be carried out in the 6th-10th weeks of after bloom for fruit bagging. It also can effectively prevent fruit fly damage. The weather of Taiwan was warm and high humidity in summer season. This environmental climate makes the fruit growth rate much greater fast than fruits of winter season. It also causes poor fruit quality and soft texture. In order to maintain the quality of guava fruit during summer season, there are many cultivation operations such as pruning foliage, fruit thinning, Fertilization, use of different bagging materials, and adjustment the day of harvest, the results of this study suggest that the adjustment of bagging time is also a recommended method. From the 6th week to the 10th week after bloom, fruit selection and bagging operations was better for working, and the fruit has performed a better hardness and a longer growth period, and the nutrient accumulation and storage quality of the fruit should be better. |
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