A rice grower’s biggest, and smallest, enemy

Of all the challenges Trukai faces growing local rainfed rice in Papua New Guinea, our potentially biggest problem is our smallest – roughly the size of your fingernail.
Insects, you see, pose a real threat to our potential to produce commercial, domestically grown rice in PNG.
There are different rice growing cultures in the world today but the most of the efficient systems enjoy a conducive growing environment free of insects with access to abundant and relatively cheap inputs. There is significant investment in infrastructures such as irrigation, electricity, road infrastructures and farming equipment.
With respect to growing environments, the best quality rice is grown in temperate climates such as in Australia and the United States where they enjoy freedom from multiple pest pressures and longer daylengths.
The bulk of the farmers, however, are in the tropics and they often face multiple challenges posed by varying factors that significantly limit yields and quality of the rice grown.
PNG fits into the second category.
Our work has identified relatively suitable areas of growing rice in the country, however these areas host a number of insect pests that can frustrate a well-intentioned rice growing venture. There are over 100 species of insect recorded that attack rice and some of the dreaded ones have their home in our country.
Amongst these the Brown Planter Hopper (or BPH for short) has been recorded in PNG well before any rice farming was ever considered. The insect goes by a scientific name Nilparvata lugens.
This dreaded insect has a recorded history in other parts of the world of causing extensive damage to crops, impacting on food security and causing significant loss of income to rice growers in countries where rice is an important crop.
From farmers’ experience around the globe, one can expect to lose up to 60 % of the total crop yields.
The extent of its impact in our country is not visible at this stage as PNG is a relatively new environment for rice. However, as the culture of farming becomes more established, this pest as well as others will become established also, with a well-developed life cycle and ability to cause extensive loss to aspiring rice farmers and commercial growers.
There are two species or types of BPH. The common one is called BPH as depicted by its colour, while the other is white brown planter hopper (WBPH). Both are destructive but we have found the BPH to be more common in our rice fields.
The pest lives in its natural habitat and on secondary host plants – main grass species which are similar to rice crop, until they discover that there is a better, more nutritious food source which is of course our favourite food rice.
With favourable conditions, such as temperature, moisture and well fertilized crop, they will multiply very quickly and spread extensively across the rice crop before even the farmer or grower can notice as they feed, breed and multiply under the cover of the crop. The problem becomes more noticeable when pockets of areas start to turn brown and weakened crop starts
to collapse.
In our last three years of growing rice, Trukai has had number of incidences of this pest. Particularly after maximum tillering and towards flowering at a very critical stage when grains start to form. If left unchecked, they suck dry the milk and basically produce what are called ‘flats’ or empty grains.
For all the hard work that goes in, none of us would want insects to take all the goodies and leave behind an empty plate. But this the reality we face in this country while fulfilling the dream we have to create domestic rice industry.
Solutions to this problem are driven by previous and ongoing research around sourcing pest tolerant rice genetics and testing them for suitability to the PNG production systems. It is in this way that continuation of our previous rice research is a critical factor in establishing a sustainable local industry.
I will discuss a more about confronting this special challenge head-on, in my next column.

•  Humphrey Saese is Rice Development Manager for Papua New Guinea’s leading rice supplier, Trukai Industries. Humphrey welcomes reader feedback or new story suggestions at [email protected]