Pests grow with sunflower

The sunflower (

), a plant originating in North America, belongs to the Compositae family, is cultivated in various parts of the world and currently has around 18 million hectares planted.

In Brazil, crop growth in relation to planted area has been on the rise for at least three harvests. The planted area across the country did not exceed 5 thousand hectares just two years ago, and increased to 22 thousand in the 97/98 harvest. In the state of Goiás alone, growth totaled 6 thousand ha. In the 98/99 agricultural year, the planted area continued to rise and reached 82 thousand ha, with 65 thousand in the Central-West region where the state of Goiás already accounts for 34 thousand ha. If the advance in culture observed in recent years is confirmed, the projected cultivated area for the year 2000 throughout the country is approximately 160 thousand hectares.

The possibility of an alternative crop for the off-season, with a production cost of 20 to 25% cheaper than corn and the various uses of sunflower, explain the interest of Brazilian farmers. The production of oil for various purposes, bran for human and animal consumption, pharmaceuticals, cosmetics, among others - all with good market acceptance - are the main destinations for sunflower.

Sunflower pests

It is no surprise that the introduction of a crop always comes with insects and diseases associated with it. It is no different with sunflower cultivation and some pests are already beginning to worry, as the rapid increase in planted area has also favored an increase in pests, some of which were considered, until now, secondary to sunflower,

Most of the pests observed in sunflower crops to date are already known in other crops. And that's why handling and control become easier. However, it remains to be defined - at least for most species - the levels of damage at which the drop in production is significant.

The most important sunflower pest species vary according to the crop's development stage. Combating it is more problematic during flowering, as, in addition to the difficulty for machines to enter due to the tall size of the plants, the use of insecticides that are harmful to pollinators, especially bees and natural enemies, must be avoided.

In the initial phase of the culture, the most important pests are the brown stink bug, screwworm and some beetle larvae such as cowbird and capitulum beetle. After the crop is established until flowering, the greatest damage is caused by defoliating caterpillars such as the false bollworm, soybean bollworm and cotton bollworm, as well as beetles, including the cowworm. In the fruiting phase, stink bugs and capitulum beetles are the most important pests.

In addition to the insects listed below, there are others, generally of less importance, but which should also be monitored. Example: ants, leaf miners, Idi amim (

),

Etc. ...

Chapter Beetle

– In the juvenile stages (egg, larva and pupa) it lives in the soil. Soon after the larvae hatch, they begin to feed on the roots of host plants, slowing their growth and damaging production. In adulthood, it feeds on sunflower heads and seeds. In the Central-West region, where the largest production of the crop is concentrated, this insect has been occurring in greater numbers in the months of January to March, although at the beginning of the rains (October) it is already easily found.

Chrysomelidae beetle

– Several species of beetles from the Chrysomelidae family are crop pests. Most attack the roots in the larval stage and damage the leaves in the adult stage. This species is most frequently observed attacking sunflower leaves and stems. However, it is important to be aware of the possibility of attacks on roots and seeds during planting.

Kitty or Patriot

- The little cow is one of several species of small beetles belonging to the Chrysomelidae family, and are important pests in the larval and adult stages. For sunflowers in particular, adults remain the most important. They attack leaves, stems and heads, however, the larvae must also be monitored because, like other crops such as corn, they can become harmful if they attack the roots.

Brown Bedbug

- It is a polyphagous pest that has increased its occurrence in certain regions. It is difficult to control and can cause great damage. Monitoring the soil during preparation is the most appropriate way of prevention. Control is quite difficult due to the depth at which they can remain in the soil. And it must be preventive at the time of planting, with seed treatment or in the furrow, although none of the prevention measures are completely effective. In soils with a history of the presence of the brown stink bug, preparation with plowing and harrowing is recommended. It is also important to avoid weeds during the crop's vegetative cycle and between harvests.

Green Bedbug

– Unlike soybeans - the main host plant of this species - it has not been observed attacking the seed (achene) of the sunflower, but rather the stem. As the population of this bug is greatest between the months of December and March and sunflower planting is generally done in February, the greatest care must be taken in the first 30 days after germination. Furthermore, this is the period of greatest vulnerability of the crop, not only to the green stink bug, but also to several other pests.

Small Bedbug

– It is a stink bug from the Pentatomidae family that attacks several crops. It is an important pest, also of sunflower, during the fruiting phase, when it attacks the heads.

Brown Bedbug

– In addition to other crops, such as soybeans, this insect can cause damage to sunflower crops, damaging the heads.

Stink Bug

– It is a bedbug from the Lygaeidae family that attacks the capitellum. In certain regions with a low population, it is not an important pest. In the Midwest, several sunflower producers have recorded significant damage caused by this insect.

Sunflower Caterpillar

– It is the most important pest of culture. It attacks leaves and stems and, in case of severe occurrence, can completely make production unviable. The caterpillars live for around 20 days, are orange in color with dark hairs (bristles) and live in groups. The pupal stage lasts one week. Then, the adults emerge, which are orange butterflies with black spots. The butterflies lay their eggs on the leaves and in just over a week the caterpillars hatch again.

Soybean caterpillar

– This is the main pest of soybeans and could become one of the most important in sunflower, as it can feed on the leaves and damage the heads. So far the attack is not severe, however, it is a pest that causes concern, as it is well adapted and is already resistant to several insecticides.

screwworm

- Moths from the Noctuidae family, well known throughout Brazil. The caterpillar is grayish or brown in color, depending on the stage of development. On new plants, caterpillars can attack the roots and cut the sunflower stem close to the ground. The moths are medium-sized (35mm wingspan), dark forewings and light-colored hindwings.

False Measure

– It is a defoliating caterpillar belonging to the Noctuidae family. In the Central-West region it does not occur very frequently, but with the advancement of the crop it is expected that it will be present in the next harvests. The caterpillar is light green in color, with two white lines along its body, and has three pairs of false legs. The adult is a moth with dark colored forewings with a shiny spot and light yellow hindwings.

Amabílio Aires de Camargo and Renato Fernando Amábile

Embrapa Cerrados