A pictoral explanation of pollination and fruiting in ash gourd crop (benincasa hispida) by Pritham 'metal farmer' Dsouza
click the photos to enlarge
above is a typical ash gourd patch, with flowering & fruit setting in progress. If one looks closely, there are several irregularities in flower size, leaf color & fruit formation. I hope to show case the process of pollination & some of the problems faced wrt insects & caterpillars thru a set of photos which i have personally clicked.
the above pic shows the growing tip of the vine, which in normal circumstances looks fine.
a closer look reveals that the plant may be suffering from Phyllody, which is caused by leaf hoppers. all the nodes and internodes of the plant get shrunk & give a mottled appearance as seen above. malformation of axillary buds is visible & the leaves fail to attain full size.
Management: safest, & least toxic way is to use dimethoate @2 ml per litre of water , min of 5 sprays every 10 days to prevent the spread of the plant hoppers
above pic shows the development of the buds into flower buds
the above pic is a female flower, notice the round bulge at the bottom of the flower. after pollination , fertilization takes place resulting in the formation of the fruit
a normal ash gourd flower, yet to bloom
the above pic shows the well defined ash gorud flower, bright yellow in color, almost perfect
the above 2 pics shows pollination being done by honey bees. the bright yellow color attracts more than just normal honey bees, but wasps, hornets, butterflies & other pollen collectors.
zoomed pic of honey bee collecting pollen
a tiny wasp collects pollen, but look at the next photo, i have zoomed to show another parastic pest infesting the flower
in the centre, lies the leaf eating caterpillar. (Diaphania indica)
same photo zoomed below
a more clear photo above shows both the insects at work. the bee is busy with its pollen collection, while the caterpillar looks for a place to hide.
the easiest way to detect is to look for excreta of the caterpillar which is generally in pellet form and can be seen in the above photo.
in many cases the caterpillar completely bores a hole in the flower and then the yield is affected severly.
the photo above shows a flower that has already dropped off due to attack by the caterpillar.
once the caterpillar is a bit bigger, it starts to feed on the leaves & as seen in the above pics, causes irreversible damage to the leaves. also notice a pattern of irregular lines, vein banding in the form of a mosaic appearance. it is a virus & is another serious problem caused by aphids and white flies.
Management:
- the caterpillars can be totally controlled by using a combination of profenophos with chlopopyriphos @ 2 ml per litre of water. high concentration neem sprays is effective & neem cake can be used in the soil . just before the caterpillars enter pupal stage, they start to weave a silk coccoon, which is resistant to sprays. so the timing of sprays is very important.
- aphids can be effectively controlled using garlic sprays, neem sprays(10 ml per litre) and low dose of dimethoate @ 1 ml per litre of water
the forming fruit seen above
if the vines are healthy, fruit formation can be seen at every inter node as seen above.
a much larger size fruit about the size of a tennis ball. one can see formation of ash, from the top
some tender fruits fall prey to daucus cucurbitae fruit fly. the fly bores the fruit & it slowly starts to bleed as seen above. this secretion attracts more harmful insects & the wound is perfect for fungas to thrive.
also after the fruit is formed, one can see the excreta of caterpillars on it. this must be cleaned off before marketing the produce. the excreta fell from the leaves on to the fruit.
in some cases, the developing fruit bud suddenly gets heavily discoloured & dies. there may be several reasons like fruit necrosis or fruit fly.
Management- fruit necrosis is caused by a virus transmitted by thrips & can be treated with dimethoate @ 2ml per litre at every 12 days interval.
- fruit flies can be controlled by using pheromone baits, click here for more
ash gourd can be harvested in about 100 days after sowing. the fruit will ahve a total ash covering & the growing tendril with it starts to dry off. sometimes tapping the fruit to get the desired 'thunk' is also another harvest index.
all photos and content by Pritham 'metal farmer' Denzil Dsouza
for the above trap, i took discarded cornflakes box & flattened them. then using scissors, i cut out the required amount of yellow plastic sheet (easily available in the market) and stapled it to the cardboard box as seen.
the next day, i could see thousands of tiny white spots all spread over the sticky trap. (click on photo to enlarge)
my first impression was , it could have been dust. but on a closer look, it turned out to be the pesky white fly which got caught in the sticky trap & choked to death.(click on photo to enlarge)
the above pic shows an area of about 2 sq inches. (click on photo to enlarge)
