Field Notes May 31, 2010; borers, algae, salt injury

Midrib damaged by rice stalk borer

Usually we find borers in the stem of the rice plant, but in this case a borer had entered the midrib of the leaf.  The first instars of the borer are small enough to bore into the midrib.

Early instar rice stalk borer

The rice stalk borer can be distinguished from the Mexican rice borer by the color of its head capsule and the lines on its back.  The head capsule of the Mexican rice borer would have been a lighter brown and the lines on its back would be broken and appear as a series of dashes.  Here it is clear the rice stalk borer has a dark head capsule and the lines on its back are continuous.

Algae (scum) in rice

Most of the time an algal bloom causes problems in rice especially if it is young.  In those cases wind can push the layer of algae over the top of seedlings and literally starve them of sunlight.  When an algal bloom occurs in older rice it can be beneficial because it will shade out weeds underneath it.

Salt injury to rice

The inverted “V” pattern on the leaf tip is indicative of some sort of nutrient toxicity.  This pattern used to be common in corn when we used to side dress it with high rates of potassium fertilizer.  In that case it was usually a temporary problem.  We checked the well being used to irrigate this field and found high levels of both sodium and chlorides and total soluble salts.  The field had been flushed and flushing aggravates salt problems.


Tags: , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: