Mosquitoes and mangoes

It was exactly 24 years ago last Tuesday that I wrote this piece about the birds, the bees, the backyard mango crop, mosquitoes (Aedes aegypti, of course), Malathion and yellow fever.

Re-reading this piece in 2003, set me wondering whether that pesticide is still as effective as it was way back in ’79, and what effect it could have on the latest insect immigrant, the Asian ‘Tiger’ mosquito, Aedes albopictus, last seen hovering around Chaguaramas. Which reminds me, I hear that, as a precaution, since the yellow fever virus is known to lurk in the Chaguaramas area and the Asian Tiger appears to be more efficient at transmitting the virus than the Aedes aegypti, schoolchildren are being vaccinated against yellow fever. Before we see what I wrote so long ago, did you know that, to be on the safe side, the CDC (Centres for Disease Control) in Atlanta, Georgia, USA, recommends booster shots for yellow fever every 10 years? Meanwhile in ’79: “If the flowering heads on the trees in our backyard are any indication, we’re going to have a bumper crop of mangoes this year. Our pear tree is looking good, too. Although the promised “ever-bearing lime” has only one very lonely blossom, the soursop’s yellow-green lantern flowers should be keeping the birds well fed in a few months’ time.

In fact if it weren’t for the evidence of the grapefruit, one could confidently predict that this year the backyards of Trinidad will well repay their owners the trouble and expense of pruning away the bird-vine, fertilising and spraying. Unfortunately, the grapefruit has another story to tell. Blossoms that looked so abundant and smelled so strong last year, never lived up to their promise. Three or four years ago our forecasts of a bumper crop would have come to pass. Three or four years ago we couldn’t even give the fruit away because everyone we knew already had more than they knew what to do with. Today each backyard tree had only 50 or, at most, 100 fruits so that we are having to buy grapefruit in the Central Market. What has gone wrong? The flowers on the early-fruiting mangoes have dried up, leaving no trace of setting fruit. Will the other mangoes, the zaboca, the soursop and the lone lime flower go the same way? Will they dry up, drop off and leave no ripening fruit behind? And if so why? What, apart from the Pan Trinbago ban (?) and yellow fever, is so different about this year?

Carnival is over and most of us have had our yellow fever “shots” already. We’ve all survived the spraying programme. As promised, those aerial shower baths only hurt the bees and other uninteresting insects — although more than one backyard mosquito seems to have survived to bite another day. It is only the beekeepers and nature food nuts desperate for honey who will suffer, isn’t it? Or isn’t it? What about the birds and the bees? In spite of the warnings to owners of pets in cages, our wild birds appear to have lived through the spraying — which is bad news for the remaining mangoes and soursops but good news for the gardeners who believe in letting nature take her course.

Not all birds ruin our backyard fruit by taking a quick peck at a half-ripe mango. There are birds that prefer a tasty insect, caterpillars and fruit flies are their preferred fast foods. As Malathion is not a residual poison (that is, if it doesn’t kill at once it, quite literally, won’t harm a fly) our wild birds seem to have escaped the slaughter. So much for the birds. The bees are a very different story. Bees fly from flower to flower collecting nectar to make honey. However, since no one gets anything for nothing, those hard-working insects pay their debts to nature when they accidentally collect pollen from one flower and carry it on their bodies to another flower where they wipe off the fertilising male pollen on the sticky female stigma — and so a fruit is conceived. And that, children, is how great-great-grandfather explained to great grandfather where babies came from.

As far as it went, that explanation was as true then as it is today— but there is more, as great-grandfather learned, and you will, now. Honey bees are not the only insects to live on nectar and so, quite unintentionally, fertilise the flowers. Or, to be exact, the eggs in the ovaries of flowers. How many unprotected, undomesticated yet economically useful insects breathed their last in the choking clouds of Malathion spray we can’t even begin to guess (2003, one trembles for the fate of Anagyryus — the wasp that rescued us from the devastating pink mealybug in ‘96 and ‘97). We may get a rough idea of the effects of spraying when the mango season comes and we see how many, or how few mangoes are in the market. If zaboca in season cost $2, $3 or more dollars each, we will know what the sprays have done.

Only then shall we know what damage had to be done by the Malathion. It had to be done to save our lives. And yet our lives, ironically enough, depend entirely on food, food that comes from plants, or food that comes from animals that eat plants. Only then shall we learn the hard lesson that many of our food plants need, must have, can’t have sex without birds and insects as go-betweens. So, what have we saved with Malathion sprays? Our lives. But precious little else — as we may discover in due course while shopping for fruits and vegetables in the Central Market . . .” Final 2003 note. Have you covered your water tanks, cleaned out the formicles, let the Insect Vector people inspect your premises? Or would you rather have dengue, DSS, DHS and . . . ?