Ecology and Sustainable Management of Major Bactrocera Fruit Flies in Goa, India V. R. Satarkar, S. V. Krishnamurthy, J.R. Faleiro, A. Verghese, R. Ramesh and J. Ashok Kumar Email: vved20@yahoo.co.in jrfaleiro@yahoo.co.in
INTRODUCTION Fruit flies are an important group of insects that occur across India. This Tephritidae family consists of over 4500 species of thefruitfliesintheworldofwhich200 species are of economic importance. They are among the most important world wide because of their direct economic impact and strict quarantine implications.
Technical details Series of field and laboratories experiments were conducted from April 2006 to March 2008. For trapping, three villages were selected in the coastal, midland and upland regions of Goa. Trapping was done by using methyl eugenol and cu lure traps Trials on Management of B. cucurbitae (BAT) and B. dorsalis (HWT) were taken up.
Old Goa Coastal zone 10km from Arabian sea/15m above MSL Keri Midland zone 25km from Arabian sea/70m above MSL Molem Upland zone 50km from Arabian sea/100m above MSL The midland and upland form a part of Western Ghats (mountainous region ) biodiversity hot spot Study sites
Fabrication of Bottle Trap 1. Fabricated using disposable plastic water bottles (capacity: 1L). 2. Each trap had four windows of 1 square inch, cut open just below the shoulder of the bottle. 3. For facilitating the recording of data with respect to flies captured, the bottom of the bottle trap was cut and reversed into the open lower end of the bottle. 4. The trap was loaded separately with Methyl Eugenol (ME) block and Cue Lure (CL) block. ME blocks were prepared using plywood pieces of 5 X 5 X 1.2 cm which were soaked overnight in a mixture of ethanol solvent, ME and 0.1%malathion50ECinaratioof 6:4:1 by volume, while the CL blocks were procured from a commercial dealer Suspension thread Opening for entry of fly Wooden block dipped in attractant Small holes for water draining
Cue lure trap Methyl eugenol trap
Each trap was set 1 km apart from the other in the above selected three ecological zones. At each study site, 16 traps (8 traps each with ME and CL) were set. Each trap was fastened with the help of small nylon ropes to the twigs of the trees at 2m height. Number of flies trapped in each trap was recorded at weekly intervals. The lures were replaced at bimonthly intervals in order to sustain the trapping efficiency. The captured flies were brought to the laboratory, dried, separated species wise and were preserved.
Ecology
Incidence and abundance of Orchard and Melon flies Orchard flies (ME) Melon flies (CL) Bactrocera dorsalis (Hendel) Bactrocera caryeae (Kapoor) Bactrocera zonata (Saunders) Bactrocera affinis (Hardy) Bactrocera correcta (Bezzi) Bactrocera cucurbitae (Coquillett) Bactrocera tau (Walker) Bactrocera gavisa (Munro) Bactrocera caudata (Fabricius) Bactrocera nigrotibialis (Perkins)
Incidence (%) of fruit flies at three geographical zones of Goa Species Percent incidence ANOVA Upland Midland Coastal F p B. caryeae 95.25 98.11 81.13 8.235 0.001* Orchard flies B. dorsalis 100 98.12 100 11.248 0.001* B. zonata 59.43 39.62 48.11 2.911 0.056 B. correcta 41.50 40.56 51.88 2.179 0.115 B. affinis 10.37 2.80 3.77 2.040 0.132 B. cucurbitae 98.11 100 100 23.507 0.0001* Melon flies B. tau 53.78 76.41 59.43 6.643 0.001* B. gavisa 19.81 17.92 29.24 4.203 0.016* B. caudata 0.04 3.77 19.81 13.256 0.0001* B. nigrotibialis 16.03 14.15 2.83 5.565 0.004* * Significant at 0.05 level.
Spatio-temporal occurrence and abundance of orchard flies Mean density (No/trap/month) 18 16 14 12 10 8 6 4 2 0 B. caryeae B. dorsalis B. affinis B. zonata B. correcta Species Mean density (Number/trap/month) of orchard flies in Goa
Spatio-temporal occurrence and abundance of melon flies Mean density (Number/trap/month) of melon flies in Goa.
Rank Abundance of orchard and melon flies 0.4 0.3 B. caryeae B. dorsalis UPLAND Pi Pi 0.2 0.1 0 0.5 0.4 0.3 0.2 0.1 0 0.4 0.3 B. cucurbitae B. zonata B. tau B. correcta 1 2 3 4 5 6 7 8 9 10 B. caryeae Rank B. gavisa B. nigrotibialis B. affinis B. caudata B. dorsalis B. gavisa B. tau B. cucurbitae B. nigrotibialis B. correcta B. caudata B. zonata B. affinis 1 2 3 4 5 6 7 8 9 10 B. cucurbitae B. dorsalis Species Rank MIDLAND COASTAL Pi 0.2 0.1 0 B. caryeae B. tau B. gavisa B. correcta B. caudata B. zonata B. affinis B. nigrotibialis 1 2 3 4 5 6 7 8 9 10 Rank Species Melon flies are indicated in red and orchard flies are in black letters
Spatial Distribution pattern of Orchard flies Parameters/Index Upland Midland Coastal Variance to Mean ratio 184.13 194.49 1257.33 Maximum regularity (1/n) 0.0094 0.0094 0.0094 Cole s Index Randomness (1/n + (n 1)/n X 1/ X) 0.0094 0.0094 0.0095 Index value (I) 0.023 0.018 0.055 David Moore`s Index 183.13 193.49 1256.33 Dispersion Parameter (K) 0.693 1.098 0.0205 Common K 0.684 1.089 0.196 Llyod`s Index (X*) 310.08 406.03 1514.38 Morisita`s Index 2.43 1.90 5.82 Dispersion indices for orchard flies at three geographical zones
Spatial Distribution pattern of melon flies Parameters/Index Upland Midland Coastal Variance to Mean ratio 60.52 213.34 391.38 Maximum regularity (1/n) 0.0094 0.0094 0.0094 Coles Index Randomness (1/n + (n 1)/n X 1/ X) 0.0094 0.0095 0.0096 Index value (I) 0.017 0.022 0.027 David Moore`s Index 59.523 212.343 390.382 Dispersion Parameter K 1.227 0.748 0.547 Common K 1.217 0.739 0.537 Llyod`s Index (X*) 132.551 371.277 603.768 Morisita`s Index 1.807 2.324 2.812 Dispersion indices for melon flies at three geographical zones
Seasonality 1600 1400 1200 Abundance 1000 800 600 400 200 0 Pre monsoon Monsoon Post monsoon Season Orchard flies Melon flies Abundance of orchard and melon flies recorded during pre monsoon, monsoon and post monsoon seasons.
1200 Orchard flies Melon flies Mean Montly abundance (Nos/trap) 1000 800 600 400 200 0 B. dorsalis B. caryeae B. zonata B. affinis B. correcta B. cucurbitae B. tau B. gavisa B. caudata B nigrotibialis Species Pre monsoon Monsoon Post monsoon Mean density of orchard and melon flies (Numbers/trap/season ±SE) recorded during different seasons
Phylogenetic Relationship
Dendrogramme showing phylogenetic relationship of major fruit flies in 3 different ecological zones
Management of B. cucurbitae and B. dorsalis
A view of the hill cucurbit agro-ecosystem in Goa
Different cucurbits cultivated in the Western Ghats region of Goa Ridge gourd Red Pumpkin Cucumber Bitter gourd Snake gourd
Traditionally preserved cucurbit seeds by tribal farmers of Goa, India Crop production to marketing
Melon fly, Bactrocera cucurbitae is a major pest, causing more than 20 % loss in the yield. Bactrocera cucurbitae infested cucumbers B. cucurbitae infested cucumber vines
Farmers sometimes use insecticides to control B. cucurbitae A potential hazard to children of the tribal farmers in the agro ecosystems
A B A B B A Cage used for Single Killing Point study
Sl No. Treatment Mean SD t 1 Standard PH as spray 5.17 0.753 0.542 Standard PH as spray 4.83 2 Standard PH as spray 5.50 0.775 1.581 Standard banana as spray 4.50 3 Standard PH as spray 5.67 1.722 0.948 Standard jaggery spray 4.33 4 Standard PH as spray 4.83 0.606 0.674 Standard banana spray double dose 5.17 5 Standard PH as spray 4.25 1.369 1.342 Standard jaggery spray double dose 5.75 6 Standard PH as spray 5.92 1.563 1.437 St. jaggery spray + st.banana spray 4.08 7 Standard PH as spray 4.58 0.917 1.112 St. jaggery spray + st.banana spray + tuna spray 5.42 8 Standard jaggery spray 5.08 1.021 0.200 Standard jaggery trap 4.92 9 Standard banana as spray 5.33 0.983 0.830 Standard banana trap 4.67 10 Standard PH as spray 5.50 0.894 1.369 Standard PH as trap 4.50 11 Standard PH as trap 5.50 0.707 1.732 Standard banana trap 4.50 12 Standard PH as trap 4.83 0.258 1.581 Standard jaggery trap 5.17 13 St. jaggery spray + st.banana spray 5.17 0.753 0.542 St. jaggery spray+ st.banana spray + tuna spray 4.83 Attraction of B. cucurbitae to different baits in single killing point Studies
Treatments tested in cucumber field 1. Commercial PH (obtained from Anand Agricultural University,Gujarat) made up as a solution with 1L water containing 30ml of PH (3% volume: volume) 2.Banana (velchi) made as 10g banana mashed up and liquidized in 1L of water (10% weight: volume) 3. Jaggery + banana mixture, made up as 5g of jaggery and 5g of banana in 1L of water (5% jaggery and 5%banana weight: volume) 4. Insecticide sprays (0.1% malathion 50EC) 5. Untreated control (no bait / insecticide application) (1-4: In farmers field, 5: Institute farm)
Squirting of the Baits 8L/ha @200 splashes/ha (each splash 40ml) Applied in a 7m square grid Weekly application 30days after planting up to end of commercial fruit production
On farm Bait Application Technique (BAT) to control B. cucurbitae Sl. No Treatments Percent damage Trial I Trial II Trial III Pooled mean 1 Protein Hydrolysate 17.38 (10.74) b 11.15 (3.80)bc 14.38 (6.28)b 15.02 (6.94) bc 2 Banana 13.31 (05.38) bc 13.16 (5.41)b 16.61 (8.23)b 14.51 (6.33)bc 3 Banana +Jaggery 13.26 (13.26) bc 09.19 (2.60)c 11.41 (4.05)c 11.55 (4.28)cd 4 Insecticide 06.54 (01.32) c 10.09 (3.08)bc 10.48 (3.37)c 09.25 (2.59) d 5 Control 26.50 (21.00) a 26.58 (20.24)a 25.70 (18.86)a 26.47 (20.04) a CD (p =0.05) 7.43 3.53 2.96 3.26 Values in parenthesis denote original value
Cost benefit ratio of BAT in hill cucurbits of Goa to manage B. cucurbitae Average yield of hill cucumber in Goa 30t/ha Cumulative damage due to B. cucurbitae in control plot 20.04 % Cumulative damage due to B. cucurbitae in treated plot 4.28 % Loss in yield that was saved due to treatment 15.76 % (4.7 t/ha ) Estimated gain due to treatment Rs 30,550 (@ Rs. 6500/t ) Cost of treatment (10 applications) Rs 2000 / ha Cost Benefit ratio 1: 15.3
Hot water Treatment
Mass rearing of fruit fly
Freshly harvested mangoes Fruits exposed overnight to fruit flies
Hot Water Treatment
Hot water treated mangoes (48 cfor1hr/48 c for 1.5 hr/untreated control) Sensitivity tests (Colour, aroma sweetness)
Good Very Good Poor Good Very Good Poor Respondents (%) 70 60 50 40 30 20 10 63.33 32.78 65.74 58.15 28.70 27.41 3.89 5.56 14.44 Respondents (%) 60 50 40 30 20 10 48.15 48.33 46.30 42.78 5.93 8.89 52.04 31.67 16.30 0 48oC at 1hr 48oC at 1.5hr Control Hot water treatments of mangoes (Colour) 0 48oC at 1hr 48oC at 1.5hr Control Hot water treatments of mangoes (Sweetness) Good Very Good Poor Respondents (%) 70 60 50 40 30 20 10 0 62.78 64.63 58.33 28.89 24.81 16.85 18.15 17.22 8.70 48oC at 1hr 48oC at 1.5hr Control Hot water treatment of mangoes (Aroma) Sensitivity tests (colour, sweetness, aroma)