“Key Informant Survey” of Production, Value, Losses and ... - DfID

economic damage per fly will be greater at small population sizes than at large ones. Additionally, several control
studies (e.g. Qureshi et al., 1981, Marwat et al., 1982) have assessed fly control as differences in total
emergences of pupae per number or mass of fruit: these values can only be converted into infestation rates, and
thus economic losses, if the distribution of larvae among fruit is known.
A check was also made on the ability of parapheromone lure traps to convey information about fruit
infestation. Traps allow the quick and cheap monitoring of fly populations, potentially useful both for general
population monitoring and for on-farm threshold estimates to deploy controls, but they are difficult to calibrate to
infestation ((Nasir Uddin et al., 2000b).
Control research focussed on the potential benefits of the use of Bait Application Technique (BAT) and
soaked-block Male Annihilation Technique (MAT). Neither of these technique is in farm use in Pakistan.
BAT deploys spots of protein bait mixed with insecticide; adult insects are attracted to these, feed from
them and are killed (Rossler, 1989). Per unit surface area, BAT may use less than 10% of the insecticide content of
cover sprays, and thus is cheaper and less polluting. Bees and parasitoids are not attracted to the protein, and
deposits may be positioned to minimise exposure of humans and domestic animals. BAT has been successfully
evaluated in Pakistan (Latif et al., 1987) but not widely adopted.
MAT exploits the attraction of male fruit flies to parapheromones to eradicate males so that flies cannot
reproduce (Cunningham, 1989). It involves less expense, insecticide and threat to humans and non-target
organisms even than BAT. In Pakistan MAT has been shown substantially to reduce fly populations in guava
(Marwat et al., 1992; Qureshi et al., 1981) and mango (Mohyuddin and Mahmood, 1993). It has hitherto used
plastic traps containing cotton wicks soaked in lure, which can be expensive, needing regular reloading and
emptying, and vulnerable to sunlight, wind and theft; these shortcomings can be remedied if traps are replaced
by wooden blocks soaked in lure and insecticide which can be nailed or hung in trees - male flies are attracted to
the blocks, feed from their surfaces and are killed. In Mauritius, a block programme has successfully maintained
low levels of flies over large areas (Permalloo et al., 2001).
Materials and Methods
Fruit and flies were sampled on farms from a variety of zones, farms, years and seasons, together
labelled “sites”, around Rahim Yar (RY) Khan (28 o 24'N, 70 o 19'E, by ZC) and Faisalabad (31 o 22'N, 73 o 3'E, by GM), in
the Punjab, and Mardan (34 o 13'N, 72 o 4'E, by AM) and Dera Ismail (DI) Khan (31 o 51'N, 70 o 56'E, by KB), in the
North West Frontier Province. The four are spread over an area of over 100 000Km 2 .
BAT and MAT were deployed on farms for comparison with farmer controls under field conditions (in
fact all no-control, with the sole exception of guavas in Mardan, protected by cover sprays of insecticide). BAT
was assessed in guava (Psidium guajava; DI Khan, 1998, two farms; RY Khan, 1998, two farms; Mardan, 1998,
one farm; fields between one and five Ha), jujube (Ziziphus jujuba; DI Khan, 1998, one farm, and 1999, one farm,
Faisalabad, 1999, one farm; fields between 0.4 and 4.5Ha) and melon (Cucumis melo; RY Khan, 1999, two farms;
DI Khan, 1999, two farms; Faisalabad, 1999, one farm; fields between 0.4 and 5.5Ha). Soaked-block MAT was
evaluated on mango (Mangifera indica) in RY Khan in 1999 on four farms (fields between 2.4 and 6.0Ha). Two
other crops - persimmon (Diospyros virginiana; Mardan, 1998, one farm) and luffa (Luffa aegyptiaca; RY Khan,
1998, two farms) - were evaluated but trials discontinued after late starts and small sample sizes indicated few
useful results could be expected.
The study served as both a survey of loss levels and distributions and a comparative trial of control
technologies. Fieldwork encountered difficult conditions, relying on public transport for field visits, and at risk to
larval mortality in rearing laboratories whose temperature and humidity could not be controlled, and to the loss of
crops to other causes such as drought and the theft of fruit (and equipment) from fields. As a result, the datagathering
process was intended to be as robust as possible, with overlapping use of different assessment
methods to back each other up. A standardized research data set was developed to allow both the comparison of
controls and farm-by-farm evaluation of distribution. Data gathering was facilitated when in 1999 loose data
record sheets were replaced with purpose-written comb -bound data books of empty tables for the recording of all
variables from one field in one season, together with a manual for filling in the data books, with worked examples.
Similarly, data analysis was facilitated by the development of a standard spreadsheet template of statistical
operations, laid out to mirror the data sheets, onto which field data could be copied for standardised processing.
Experimental controls were deployed by farmers or researchers. BAT sprays were of a preparation of 3ml
of malathion 57% a.i. E.C. (“Fifinone” obtained locally) and 30ml of commercial protein (International Pheromone
Systems Ltd, Ellesmere Port, South Wirral, CH65 4TY, UK. ips_ltd@btconnect.com) in 1l of water, applied in
discrete spots at a rate of 7.5l.Ha -1 . Application was by farmers or researchers depending on circumstances, with
standard lever-operated knapsack sprayers. Following guidance from the Mauritian National Programme, MAT
blocks were of 5x5cm squares of 1.2cm thickness commercial plywood, soaked in a mixture of 95% ethanol
solvent obtained locally, technical methyl eugenol (International Pheromone Systems Ltd) and malathion
(“Fifinone”) in a v:v:v ratio of 6:4:1. Blocks were soaked for approximately twelve days, allowed to dry for
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