Ecology and Sustainable Management of Major Bactrocera Fruit Flies in Goa, India

Transcription

1 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

2 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.

3 Technical details Series of field and laboratories experiments were conducted from April 2006 to March 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.

4 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

5 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

6 Cue lure trap Methyl eugenol trap

7 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.

8 Ecology

9 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)

10 Incidence (%) of fruit flies at three geographical zones of Goa Species Percent incidence ANOVA Upland Midland Coastal F p B. caryeae * Orchard flies B. dorsalis * B. zonata B. correcta B. affinis B. cucurbitae * Melon flies B. tau * B. gavisa * B. caudata * B. nigrotibialis * * Significant at 0.05 level.

11 Spatio-temporal occurrence and abundance of orchard flies Mean density (No/trap/month) B. caryeae B. dorsalis B. affinis B. zonata B. correcta Species Mean density (Number/trap/month) of orchard flies in Goa

12 Spatio-temporal occurrence and abundance of melon flies Mean density (Number/trap/month) of melon flies in Goa.

13 Rank Abundance of orchard and melon flies B. caryeae B. dorsalis UPLAND Pi Pi B. cucurbitae B. zonata B. tau B. correcta 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 B. cucurbitae B. dorsalis Species Rank MIDLAND COASTAL Pi B. caryeae B. tau B. gavisa B. correcta B. caudata B. zonata B. affinis B. nigrotibialis Rank Species Melon flies are indicated in red and orchard flies are in black letters

14 Spatial Distribution pattern of Orchard flies Parameters/Index Upland Midland Coastal Variance to Mean ratio Maximum regularity (1/n) Cole s Index Randomness (1/n + (n 1)/n X 1/ X) Index value (I) David Moore`s Index Dispersion Parameter (K) Common K Llyod`s Index (X*) Morisita`s Index Dispersion indices for orchard flies at three geographical zones

15 Spatial Distribution pattern of melon flies Parameters/Index Upland Midland Coastal Variance to Mean ratio Maximum regularity (1/n) Coles Index Randomness (1/n + (n 1)/n X 1/ X) Index value (I) David Moore`s Index Dispersion Parameter K Common K Llyod`s Index (X*) Morisita`s Index Dispersion indices for melon flies at three geographical zones

16 Seasonality Abundance 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.

17 1200 Orchard flies Melon flies Mean Montly abundance (Nos/trap) 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

18 Phylogenetic Relationship

19 Dendrogramme showing phylogenetic relationship of major fruit flies in 3 different ecological zones

20 Management of B. cucurbitae and B. dorsalis

21

22 A view of the hill cucurbit agro-ecosystem in Goa

23 Different cucurbits cultivated in the Western Ghats region of Goa Ridge gourd Red Pumpkin Cucumber Bitter gourd Snake gourd

24 Traditionally preserved cucurbit seeds by tribal farmers of Goa, India Crop production to marketing

25 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

26 Farmers sometimes use insecticides to control B. cucurbitae A potential hazard to children of the tribal farmers in the agro ecosystems

27 A B A B B A Cage used for Single Killing Point study

28 Sl No. Treatment Mean SD t 1 Standard PH as spray Standard PH as spray Standard PH as spray Standard banana as spray Standard PH as spray Standard jaggery spray Standard PH as spray Standard banana spray double dose Standard PH as spray Standard jaggery spray double dose Standard PH as spray St. jaggery spray + st.banana spray Standard PH as spray St. jaggery spray + st.banana spray + tuna spray Standard jaggery spray Standard jaggery trap Standard banana as spray Standard banana trap Standard PH as spray Standard PH as trap Standard PH as trap Standard banana trap Standard PH as trap Standard jaggery trap St. jaggery spray + st.banana spray St. jaggery spray+ st.banana spray + tuna spray 4.83 Attraction of B. cucurbitae to different baits in single killing point Studies

29 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)

30 Squirting of the Baits splashes/ha (each splash 40ml) Applied in a 7m square grid Weekly application 30days after planting up to end of commercial fruit production

31 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 (10.74) b (3.80)bc (6.28)b (6.94) bc 2 Banana (05.38) bc (5.41)b (8.23)b (6.33)bc 3 Banana +Jaggery (13.26) bc (2.60)c (4.05)c (4.28)cd 4 Insecticide (01.32) c (3.08)bc (3.37)c (2.59) d 5 Control (21.00) a (20.24)a (18.86)a (20.04) a CD (p =0.05) Values in parenthesis denote original value

32 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 % Cumulative damage due to B. cucurbitae in treated plot 4.28 % Loss in yield that was saved due to treatment % (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

33 Hot water Treatment

34 Mass rearing of fruit fly

35 Freshly harvested mangoes Fruits exposed overnight to fruit flies

36 Hot Water Treatment

37 Hot water treated mangoes (48 cfor1hr/48 c for 1.5 hr/untreated control) Sensitivity tests (Colour, aroma sweetness)

38 Good Very Good Poor Good Very Good Poor Respondents (%) Respondents (%) oC 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 (%) oC at 1hr 48oC at 1.5hr Control Hot water treatment of mangoes (Aroma) Sensitivity tests (colour, sweetness, aroma)

39