Monday, May 18, 2015

Getting an Early Take on Growth of Cotton Crop





Even though we’re only a month into the cotton season, this is a crucial time for the crop.
The first 30 to 40 days after planting determines the potential for the cotton crop by harvest time. Everything that takes place after the cotton plant stand is established will either maintain or decrease yields, according to UC IPM.
 
That’s why field scout Carlos Silva is taking a census of cotton fields. The exercise is called determining stand establishment. Simply put, he’s helping growers see how well the crop is growing.

Carlos follows a formula that compares the plant population per foot with the seedling rate per foot. The results will indicate if the stand is weak, ideal or growing too vigorously.
These are steps UC IPM says growers should follow to estimate the plant population:
  • Take at least four measurements from several representative areas of the field and average them.  
  • Use the table below to find the length of row that represents 1/1000th of an acre for various row widths.
  • In your field, count the total number of plants in the 1/1000th acre area and multiply by 1,000.
Valley cotton stands are generally falling in the optimal range.
The optimal rate is 40,000 to 60,000 plants per acre (PPA). The stand is considered weak if the rate is below 30,000 PPA. Excessive growth is anything over 60,000 PPA.

The best density rate also can depend on the variety and conditions. Higher densities may be better for plants growing in “low vigor situations.”

For weak stands, growers need to look for any seedling diseases or insects that could be causing the problem. Replanting should be considered for poor stands, including those with many adjacent rows without plants.

Pests can be one cause for poor stand development.
Excessive stands require thinning. UC IPM notes: “Dense plant populations, combined with conditions of adequate moisture and nutrients, can lead to rank growth, making the crop more vulnerable to insects and diseases. Depending on the cotton variety, a plant stand in excess of 60,000 plants per acre may require thinning.”

Right now, Carlos says most of his scouted fields fall in the optimal range. The plant populations fall within the 30,000 to 40,000 PPA range. “They’re in the ballpark.”
We’re sure growers are looking for a home run yield by fall.

Monday, May 11, 2015

Economic $urvival: H2O Goes from One Crop to Another



It’s the farmer’s version of “Paying Peter to Pay Paul.”

In this case, the currency is California’s equivalent to liquid gold – aka H2O, agua, aqua or water. This practice could increase as we get deeper into the growing season, according to field scout Carlos Silva.
 
Carlos says one veteran grower already has turned off the water tap to one of his three alfalfa fields just a couple months into the season, which normally runs through the early fall. But the grower is settling for just three cuttings in this field so he can use that water allotment for more profitable crops. The choice is a matter of economical survival during an unprecedented drought
.
So far, other growers appear to be moving forward and irrigating their alfalfa as they prepare for their next harvest in the coming weeks. You might recall many growers last year indicated the alfalfa season could end by June due to lack of water. But they wound up securing enough water to make it through the fall. They might not be lucky this season because of a fourth straight dry year.
 
It may be a water balancing act for alfalfa growers.
In the meantime, Carlos says pests have been under control in alfalfa. Aphids and weevils counts are relatively low. But the recent cool weather could lead to an increase in aphid counts.

Almond orchards also aren’t experiencing any significant pest threats. The same is true for cotton, Carlos points out. While he’s finding some mites in cotton, there have been enough thrips around to keep the mites in check.


Cotton seedlings have grown to about 4 inches tall.

While the dry winter and spring has pushed almond development about a month ahead of schedule this year, the cotton crop is following a rather normal growth pattern. That’s probably due to the mixture of hot and cool weather since cotton was planted last month. The seedlings are about four inches tall and averaging around four nodes.

Monday, May 4, 2015

Here’s Some Neighborly Advice on Preventing Unwanted Pest Migration



You might call it flight for survival.
 
We see it around your house after you run into a hornet’s nest, sending the winged pest buzzing away. And we see around orchards after you stomp on an ant hill, sending the bugs skittering about.

That’s what happens when a home is disturbed. Why bring this up? There’s pest management lesson here for growers. And there’s also a reminder here about being a good neighbor

Every season, we point out that pests like their homes, whether it’s a dirt road or an alfalfa field. But when their safe havens get disturbed, they’ll quickly seek a new home.

Take almond orchards. Field scout Carlos Silva has found a small uptick in spider mites in almonds during his weekly monitoring. These pests are found in dry areas, including dirt roads. They can be driven into the trees by trucks kicking up dust on nearby roads.
Keep your speed down when driving on a dirt road.

 Mites will damage foliage by sucking the cell contents from leaves. The leaves then turn yellow and drop, which ultimately reduces the crop and vegetative tree growth the following year.

To help control mites, growers regularly water down roads along the orchard margins to keep dust down. This is where being a good neighbor comes into play: Slow down when driving on roads next to almond orchards. That will be important as the weather heats up, which will make it a challenge to keep dust down.
Lygus bug found in an alfalfa field.
 
The good neighbor policy also applies to alfalfa growers whose crop borders a cotton field. Alfalfa is an ideal host for lygus bugs, which are no threat to the crop. When their home is disturbed, the pests will migrate to a new place, namely cotton. Lygus are a threat to the cotton crop from early squaring through boll set and can cause all sorts of damage – from square dropping to bolls failing to mature. Carlos says lygus numbers have been on the rise in alfalfa recently.



So here’s the hitch: Alfalfa is harvested many times during the season – on average about once of month. That means lygus can be on the move roughly every 30 days.
 Dr. Pete Goodell, a UC IPM advisor and cotton and alfalfa expert, says a good solution to stem the migration of lygus to neighboring cotton fields is to leave uncut strips of alfalfa during harvest. Lygus will travel to these strips and stay there until the next irrigation cycle. The bugs will then go back to the larger alfalfa field as the plants start growing again.

Right now, alfalfa growers have finished their second cutting of the season and have been irrigating the crop. The next harvest should come around the end of May. Goodell tells us that leaving uncut strips is vital from June to July because that time period is a critical stage for cotton development.
UC IPM offers these tips about border-strip strip harvesting: “Leave 10 to 14 foot wide uncut strips adjacent to every other irrigation border (or levee).

Here's an uncut strip of alfalfa next to a cotton field.
“At the subsequent harvest, cut half of the width of the existing strip going into one windrow and the other half going into a second windrow to give a 50:50 blend of new and old hay. These windrows are then each combined with a windrow of newly cut (100 percent new) alfalfa making a blend of 25 percent old hay and 75 percent new hay.

“This technique minimizes quality problems from the older hay. Specific blends of old and new hay have been found not to significantly impact forage quality compared to 100 percent new growth alfalfa in most cases.”

Monday, April 27, 2015

You’re All Wet if You Don’t Take Almond Disease Management Seriously in a Drought Year



Farmers are quick to tell you that no two years are the same. They come to expect the unexpected. Past performance doesn’t necessary predict future results.

Almonds are well into fruit development at this time.
This certainly is the case with almond growers. Their crop has been doing well so far this season with nuts developing about a month faster than normal.
 
“Every year is different with the progression of the crop. This year we’re ahead,” says Gurreet Brar, a farm advisor and almond expert with the University of California Cooperative Extension in Fresno County.
 
As a result, it’s important that almond growers stay on top of monitoring the trees in the orchard and not simply relying on the calendar as a guide. At this stage, almonds are well into fruit development (have you seen the size of some almonds already?)
Moisture build up can lead to diseases in trees.

Brar says growers should be looking this spring and summer for any signs of diseases in the orchards. Post-bloom diseases could linger if there is high amount of moisture in an orchard. For example, microsprinklers may be angled high up toward the canopy and that could cause moisture build-up in the canopy, creating an environment ripe for diseases to spread. Here are some of the things to look for this spring:

Alternaria damage on a leaf.  - UC IPM photos
·        Alternaria: large brown spots form on the leaf. Alternaria develops when there is a lot of humidity or stagnant air. Leaf spots can spread quickly in June and July and can completely defoliate trees by early summer.

Rust damage is evident on leaves.
·        Rust: Rust colored spores appear on leaves and can spread by air movement. It’s a serious problem in orchards near waterways or areas with high humidity in the spring and summer. Leaves can fall prematurely, causing trees to become weak.

Sacb is evident by grayish black spots the nut.
·        Scab: Grayish black spots show up on leaves, fruit and twigs in the late spring or early summer. Usually, the disease thrives during prolonged wet spring weather. As Brar points out, orchards irrigated by sprinklers can get this disease if the water reaches the foliage.

Hull rot causes leaves to wither and die.
·        Hull rot: This disease surfaces several weeks before harvest when leaves wither and die. Fungi will invade hulls and produce a toxin that kills the shoot attached to the fruit. This will impair maturity of other green fruit on the shoot. The fruit will stay on the tree after harvest. 

Brar points out the drought doesn’t have direct affect on almond tree diseases. Indirectly, though, the lack of water will weaken tree health and make them more susceptible to diseases in the future.

Reports of canker are up.
Right now, Brar has been fielding a lot of calls from growers concerned about canker in the stems and lower canopy. Called bacterial canker, this disease becomes evident in the spring and includes limb dieback with rough cankers and amber-colored gum. Also, leaf spots and a blast of young flowers, spurs and shoots can develop.

 UC IPM notes orchards with nitrogen-deficient trees, young trees 2 to 8 years old or high populations of ring nematode are prone to bacterial canker. Prevention is the best way to manage the disease. Here’s what UC IPM recommends:

  •         Maintaining proper nutrition, especially nitrogen.
  •        Applying low-biuret urea before leaf drop can reduce the canker size of infected trees.
  •      Using a nematicide treatment in October can help reduce the disease severity