Tuba controls rice pests

  By Sosimo Ma. Pablico

Powdered seeds of tuba (Croton tiglim) can effectively control the two major storage pests of rice, the rice weevil and lesser grain borer, findings of PhilRice researchers showed.

Evelyn S. Perialde, Jennifer J. Tagubase and Dr. Gerardo F. Estoy Jr. observed that tuba seed powder was even more effective than the commercial insecticides Deltamethrin and Pirimphosmethyl from one to five months in storage.  Thus, this botanical pesticide could be developed and used as alternative control against insect pests in seed storage.

In their study, the researchers first soaked the rice seeds in hot water (60oC) for 30 minutes to kill the eggs, larvae and adults of storage insect pests that may be present in the seeds.  The seeds were sun dried and then treated with tuba seed powder.

Lesser damage of 0.15 to 8 percent was noted on rice seeds treated with tuba seed powder than on those treated with Deltamethrin (0.35 -16%) from one to five months in storage.  Although damage on seeds treated with tuba seed powder and Pirimphosmethyl had similar amount of grain damage in the first month, the damage on tuba powder treated seeds became lesser from two to five months of storage. 

The germination rate of the rice seeds was not affected by the tuba seed powder.

Dr. Madonna C. Casimero, PhilRice deputy director for research and development, warned that extreme care must be exercised when gathering tuba seeds and during the process of making the powder. Tuba juice can cause blindness if it gets into the eyes.

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Solar tunnel dryer for fish drying

Dried fish and fruit processors may as well use the new model of the BPRE (Bureau of Postharvest Research and Extension) multi-commodity solar tunnel dryer (MCSTD) for faster and more hygienic drying. 

It takes a much shorter time to dry fish products than traditional sun drying.  Drying trials revealed the following drying time: alamang or soft shrimp (62.4 kg), 4 hours; espada or hairtail (41.6 kg), 4 to 5 hours; danggit or barangan (55.8 kg), 7 hours; dilis or anchovies (52 kg), 6 to 8 hours; and pusit or squid (40.3 kg), 5 to 6 hours.

The new model is made mostly of metal and has five small direct current (DC) axial   fans for variable airflow operation and reduced cost.  The flooring is made of corrugated G.I sheet, which serves as heat collector and tray rack in the drying chamber. 

BPRE engineers Robelyn E. Daquila, Romualdo C. Martinez, Baldwin G. Jallorina, Edgar D. Flores, Melanie Aileen T. Cantre, and Ruben E. Manalabe said the new model is 23 percent cheaper than the original version, as its cost is now about 70,000.  The reduced cost is attributed to the lower cost of the fan assembly and labor.  It requires only 8 man-hours to install a unit, which is 25 percent of the labor requirement of the original MCSTD.

 The MCSTD preserves the dried products longer because of lesser microbial content.  Likewise, it allows a ready supply of dried products even during lean months and uses locally available materials to suit the needs of farmers and fisher folk who put added value on their products through processing.

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Wash vegetables with soapy water to remove contaminants.

Consumers are advised to wash vegetables with soapy water to eliminate microbial contamination.  BPRE researchers have found that 50 to 100 percent of microbial contaminants are removed by half-cooking and washing with soapy water.

In their study,Ma. Cristina B. Gragasin, Agnes M. Wy, Perlina D. Sayaboc, and Miriam A. Acda monitored pesticide residue contamination in vegetables taken from farms during harvesting, trading posts, and market baskets.  They also measured the bacterial and fungal load of the vegetables.

The amount of organophosphate residues in broccoli, cabbage, cauliflower, cucumber and carrot was much lower than the maximum residue limits, indicating that these were safe for human consumption.  Lettuce had no organophosphate residue, but this could be due to the unstable nature of organophosphates.

Although carbamates were noted in some samples, the researchers said the levels may not be alarming based on the observed color reactions. While carbamates are reportedly more persistent than organophosphates, many published works have shown that washing removes most of the pesticide residues, as most of these are soluble in water.

Bruised vegetables result from improper handling.  The bruised portion becomes the entry point of microbial contaminants, which cause faster deterioration.  Three types of microbial contaminants were found as common agents of spoilage.

(For past columns, click http://sundaypunch.prepys.com/archives/category/opinion/harvest-time/ Readers may reach columnist at spablico@yahoo.com . For reactions to this column, click “Send MESSAGES, OPINIONS, COMMENTS” on default page.)